High density pixelated LED and devices and methods thereof

ABSTRACT

At least one array of LEDs (e.g., in a flip chip configuration) is supported by a substrate having a light extraction surface overlaid with at least one lumiphoric material. Light segregation elements registered with gaps between LEDs are configured to reduce interaction between emissions of different LEDs and/or lumiphoric material regions to reduce scattering and/or optical crosstalk, thereby preserving pixel-like resolution of the resulting emissions. Light segregation elements may be formed by mechanical sawing or etching to define grooves or recesses in a substrate, and filling the grooves or recesses with light-reflective or light-absorptive material. Light segregation elements external to a substrate may be defined by photolithographic patterning and etching of a sacrificial material, and/or by 3D printing.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a non-provisional of and claims priority to U.S.Provisional Patent Application No. 62/321,514 filed on Apr. 12, 2016.The entire contents of the foregoing provisional application are herebyincorporated by reference herein.

TECHNICAL FIELD

Subject matter herein relates to solid state light-emitting devices,including addressable light emitting diode (LED) array chips withreduced interaction between emissions of adjacent emitters, devicesincorporating one or more LED array chips, and LED displays andillumination apparatuses including such devices as well as relatedfabrication methods.

BACKGROUND

LEDs have been widely adopted in various illumination contexts, forbacklighting of liquid crystal display (LCD) systems (e.g., as asubstitute for cold cathode fluorescent lamps), and for sequentiallyilluminated LED displays. Applications utilizing LED arrays includevehicular headlamps, roadway illumination, light fixtures, and variousindoor, outdoor, and specialty contexts. Desirable characteristics ofLED devices include high luminous efficacy, long lifetime, and widecolor gamut.

Conventional LCD systems require color filters (e.g., red, green, andblue) that inherently reduce light utilization efficiency. Sequentialilluminated LED displays, which utilize self-emitting LEDS and dispensewith the need for backlights and color filters, provide enhanced lightutilization efficiency.

Large format multi-color sequentially illuminated LED displays(including full color LED video screens) typically include numerousindividual LED panels, packages, and/or components providing imageresolution determined by the distance between adjacent pixels or “pixelpitch.” Sequentially illuminated LED displays include “RGB” three-colordisplays with arrayed red, green and blue LEDs, and “RG” two-colordisplays may include arrayed red and green LEDs. Other colors andcombinations of colors may be used. Large format displays (e.g.,electronic billboards and stadium displays) intended for viewing fromgreat distances typically have relatively large pixel pitches andusually include discrete LED arrays with multi-color (e.g., red, green,and blue) LEDs that may be independently operated to form what appearsto a viewer to be a full color pixel. Medium-sized displays withrelatively shorter viewing distances require shorter pixel pitches(e.g., 3 mm or less), and may include panels with arrayed red, green,and blue LED components mounted on a single electronic device attachedto a driver printed circuit board (PCB) that controls the LEDs.

Various LED array applications, including (but not limited to) highresolution displays suitable for very short viewing distances, as wellas vehicular headlamps, may benefit from smaller pixel pitches; however,practical considerations have limited their implementation. Conventionalpick-and-place techniques useful for mounting LED components andpackages to PCBs may be difficult to implement in a reliable manner inhigh-density arrays with small pixel pitches. Additionally, due to theomnidirectional character of LED and phosphor emissions, it may bedifficult to prevent emissions of one LED (e.g., a first pixel) fromsignificantly overlapping emissions of another LED (e.g., a secondpixel) of an array, which would impair the effective resolution of a LEDarray device. It may also be difficult to avoid non-illuminated or“dark” zones between adjacent LEDs (e.g., pixels) to improvehomogeneity, particularly while simultaneously reducing crosstalk orlight spilling between emissions of the adjacent LEDs. The art continuesto seek improved LED array devices with small pixel pitches whileovercoming limitations associated with conventional devices andproduction methods.

SUMMARY

The present disclosure relates in various aspects to solid state lightemitting devices including at least one array of LEDs supported by asubstrate, preferably including one or more lumiphoric materialsarranged to receive emissions of at least some LEDs, and including lightsegregation elements configured to reduce interaction between emissionsof different LEDs and/or lumiphoric material regions to reducescattering and/or optical crosstalk, thereby preserving pixel-likeresolution of the resulting emissions. In certain embodiments, a LEDchip includes an array of multiple LEDs arranged on or over a growthsubstrate, a carrier substrate, and/or additional layers or substrates,with features promoting pixellation of emissions of the LED array. Incertain embodiments, an array of LEDs is provided in a flip chipconfiguration.

In one aspect, a solid state light emitting device, optionally embodiedin or incorporating a LED array chip, includes: an array of LEDssupported by a substrate and arranged to transmit LED emissions througha plurality of light-transmissive regions of the substrate; at least onelumiphoric material arranged on or over a light extraction surface ofthe substrate, wherein the at least one lumiphoric material isconfigured to receive at least a portion of the LED emissions andresponsively generate lumiphor emissions, and wherein the at least onelumiphoric material includes a plurality of light output areassubstantially registered with the plurality of light-transmissiveregions; and a plurality of light segregation elements arranged at leastpartially within the substrate, wherein light segregation elements ofthe plurality of light segregation elements are arranged betweendifferent light-transmissive regions of the plurality oflight-transmissive regions, and the plurality of light segregationelements is configured to reduce passage of LED emissions between thedifferent light-transmissive regions.

In certain embodiments, each LED of the array of LEDs is provided in aflip chip configuration. In certain embodiments, each LED of the arrayof LEDs is individually addressable. In certain embodiments, theplurality of light segregation elements extends from the lightextraction surface into an interior of the substrate.

In certain embodiments, the substrate includes a light injection surfacethat opposes the light extraction surface; and the plurality of lightsegregation elements extends from the light injection surface into aninterior of the substrate. In certain embodiments, the substrateincludes a light injection surface that opposes the light extractionsurface; a first group of light segregation elements of the plurality oflight segregation elements extends from the light injection surface intoan interior of the substrate; and a second group of light segregationelements of the plurality of light segregation elements extends from thelight extraction surface into the interior of the substrate.

In certain embodiments, the plurality of light segregation elementsincludes internal portions extending from an interior of the substrateto the light extraction surface, and includes external portionsextending beyond the light extraction surface. In certain embodiments,the solid state light emitting device further includes a plurality oflight extraction recesses bounded by the light extraction surface andthe external portions of the plurality of light segregation elements,wherein the at least one lumiphoric material is arranged at leastpartially within the plurality of light extraction recesses. In certainembodiments, the external portions are discontinuous relative to theinternal portions.

In certain embodiments, the light extraction surface defines a pluralityof light extraction recesses, and the at least one lumiphoric materialis arranged at least partially within the plurality of light extractionrecesses.

In certain embodiments, the at least one lumiphoric material includes afirst lumiphoric material corresponding to a first light output area ofthe plurality of light output areas, and a second lumiphoric materialcorresponding to a second light output area of the plurality of lightoutput areas. In certain embodiments, the first lumiphoric material isarranged to produce lumiphor emissions with a first dominant wavelength,the second lumiphoric material is arranged to produce lumiphor emissionswith a second dominant wavelength, and the second dominant wavelengthdiffers from the first dominant wavelength by at least 20 nm.

In certain embodiments, the plurality of light segregation elementsincludes a light-reflective material. In certain embodiments, theplurality of light segregation elements includes a light-absorptivematerial.

In certain embodiments, the light extraction surface is patterned,roughened, or textured to provide a varying surface to increaseextraction of light out of the substrate. In certain embodiments, theplurality of light segregation elements is registered with boundariesbetween at least some LEDs of the array of LEDs. In certain embodiments,the substrate comprises a growth substrate over which active layers ofthe array of LED were grown. In certain embodiments, the substratecomprises a carrier substrate differing from a growth substrate overwhich active layers of the array of LED were grown. In certainembodiments, the substrate is substantially continuous.

In certain embodiments, the solid state light emitting device furtherincludes a plurality of microlenses arranged over the at least onelumiphoric material, wherein each microlens is arranged over a differentlight output area of the plurality of light output areas. In certainembodiments, the plurality of microlenses includes different microlensesarranged to output light beams centered in different directions.

In certain embodiments, the present disclosure relates to a multi-colorsequentially illuminated LED display including the solid state lightemitting device as disclosed herein. In certain embodiments, the presentdisclosure relates to a light fixture including the solid state lightemitting device as disclosed herein. In certain embodiments, the presentdisclosure relates to a vehicular (e.g., automotive) headlamp includingthe solid state light emitting device as disclosed herein.

In certain embodiments, the LED emissions in combination with thelumiphor emissions are configured to produce white light.

In another aspect, a solid state light emitting device, optionallyembodied in or incorporating a LED array chip, includes: an array ofLEDs arranged to transmit LED emissions through light-transmissiveportions of a substrate; at least one lumiphoric material arranged on orover a light extraction surface of the substrate, wherein the at leastone lumiphoric material is configured to receive at least a portion ofthe LED emissions and responsively generate lumiphor emissions, whereinthe at least one lumiphoric material includes a plurality of lightoutput areas; and a plurality of light segregation elements registeredwith boundaries between at least some LEDs of the array of LEDs, whereinat least portions of the plurality of light segregation elements arearranged on or over portions of the light extraction surface and extendbeyond the plurality of light output areas. In certain embodiments, eachLED of the array of LEDs comprises a flip chip LED.

In certain embodiments, a plurality of light extraction recesses arebounded by the plurality of light segregation elements and the lightextraction surface, wherein the at least one lumiphoric material isarranged at least partially within the plurality of light extractionrecesses.

In certain embodiments, the light extraction surface defines a pluralityof light extraction recesses, and the at least one lumiphoric materialis arranged at least partially within the plurality of light extractionrecesses. In certain embodiments, portions of the plurality of lightsegregation elements extend into an interior of the substrate.

In certain embodiments, the at least one lumiphoric material includes afirst lumiphoric material and a second lumiphoric material, the firstlumiphoric material is arranged to cover a first portion of the lightextraction surface, and the second lumiphoric material is arranged tocover a second portion of the light extraction surface.

In another aspect, the present disclosure relates to a method offabricating a solid state light emitting device, optionally embodied inor incorporating a LED array chip, the method including: defining aplurality of recesses or grooves in at least one surface of alight-transmissive substrate supporting an array of LEDs, wherein theplurality of recesses or grooves is registered with boundaries betweenat least some LEDs of the array of LEDs; depositing a light-affecting(e.g., light-reflective or (less preferably) light-absorptive material)in the plurality of recesses or grooves to yield a plurality of primarylight segregation elements arranged at least partially within thesubstrate, wherein the plurality of primary light segregation elementsis configured to reduce passage of LED emissions between differentlight-transmissive regions of a plurality of light-transmissive regionsof the light-transmissive substrate; and providing at least onelumiphoric material on or over a light extraction surface of thesubstrate.

In certain embodiments, each LED of the array of LEDs is provided in aflip chip configuration. In certain embodiments, said plurality ofrecesses or grooves is defined by mechanical sawing. In certainembodiments, said plurality of recesses or grooves is defined byetching.

In certain embodiments, the method further includes defining a pluralityof light extraction recesses in the light extraction surface, whereinsaid providing at least one lumiphoric material on or over the lightextraction surface includes depositing at least a portion of the atleast one lumiphoric material in the plurality of light extractionrecesses.

In certain embodiments, the at least one lumiphoric material includes aplurality of light output areas, and the method further includesdepositing a light affecting (e.g., light-reflective orlight-absorptive) material over the at least one lumiphoric material toform a plurality of secondary light segregation elements arranged tosegregate the plurality of light output areas.

In another aspect, the present disclosure relates to a method offabricating a solid state light emitting device, optionally embodied inor incorporating a LED array chip, the method including: forming aplurality of light extraction recesses in a light extraction surface ofa substrate supporting an array of LEDs; and providing at least onelumiphoric material arranged at least partially within the plurality oflight extraction recesses.

In certain embodiments, each LED of the array of LEDs is provided in aflip chip configuration. In certain embodiments, the method furtherincludes providing a plurality of light segregation elements arranged atleast partially within the substrate, wherein the plurality of lightsegregation elements is configured to reduce passage of LED emissionsbetween different light-transmissive regions of a plurality oflight-transmissive regions of the substrate.

In certain embodiments, the method further includes forming a pluralityof light segregation elements on or over at least a portion of the lightextraction surface. In certain embodiments, the method further includesforming a plurality of light segregation elements on or over at least aportion of the at least one lumiphoric material.

In certain embodiments, the plurality of light segregation elements isregistered with boundaries between at least some LEDs of the array ofLEDs.

In another aspect, the present disclosure relates to a display deviceincluding a single light emitting device or a plurality of solid statelight emitting devices as described herein.

In another aspect, the present disclosure relates to a method ofdisplaying at least one of text and visual images using a display deviceas described herein.

In another aspect, the present disclosure relates to a method comprisingilluminating an object, a space, or an environment, utilizing a solidstate lighting device as described herein.

In another aspect, a solid state light emitting device (optionallyembodied in or incorporating a LED array chip) includes: an array ofLEDs arranged to transmit LED emissions through a plurality oflight-transmissive portions of at least one substrate; a plurality oflight segregation elements arranged at least partially within the atleast one substrate, wherein light segregation elements of the pluralityof light segregation elements are arranged between differentlight-transmissive portions of the plurality of light-transmissiveportions, the plurality of light segregation elements is configured toreduce passage of LED emissions between the different light-transmissiveportions, and the plurality of light-transmissive portions is configuredto be illuminated by the array of LEDs to define a plurality of pixelsthat includes a plurality of border portions, wherein each pixel of theplurality of pixels includes at least one border portion of theplurality of border portions; and a plurality of inter-pixel lightspreading regions configured to transmit light through border portionsof the plurality of border portions to enhance inter-pixel illuminationat light-emitting surface portions of the solid state light emittingdevice that are registered with or proximate to the plurality of lightsegregation elements.

In certain embodiments, the plurality of light segregation elementscomprises at least one light-affecting (e.g., light-reflective orlight-absorptive) material, and the plurality of inter-pixel lightspreading regions comprises at least one light-transmissive materialarranged in contact with the at least one light-reflective orlight-absorptive material.

In certain embodiments, the plurality of light segregation elements isarranged entirely within the at least one substrate; and the pluralityof inter-pixel light spreading regions includes at least onelight-transmissive material arranged at least partially within the atleast one substrate and over the plurality of light segregationelements.

In certain embodiments, the plurality of inter-pixel light spreadingregions includes at least one light-transmissive material region that iselevated relative to a surface of the at least one substrate and that isat least partially registered with the plurality of light segregationelements.

In certain embodiments, the plurality of light segregation elementscomprises a plurality of unfilled voids within portions of the at leastone substrate.

In certain embodiments, the solid state light emitting device furtherincludes at least one lumiphoric material arranged on or over a lightextraction surface of the at least one substrate, wherein the at leastone lumiphoric material is configured to receive at least a portion ofthe LED emissions and responsively generate lumiphor emissions. Incertain embodiments, the at least one lumiphoric material is furtherarranged over the plurality of inter-pixel light spreading regions. Incertain embodiments, the at least one lumiphoric material comprises alumiphoric material film that is adhered on or over the light extractionsurface of the at least one substrate.

In certain embodiments, each inter-pixel light spreading region of theplurality of inter-pixel light spreading regions comprises at least onewavelength-selective light-transmissive surface portion of the at leastone substrate. In certain embodiments, each inter-pixel light spreadingregion of the plurality of inter-pixel light spreading regions isselected from the group consisting of optical filters and opticalreflectors.

In certain embodiments, each inter-pixel light spreading region of theplurality of inter-pixel light spreading regions comprises a one-waymirror.

In certain embodiments, each light-transmissive portion of the pluralityof light-transmissive portions of the at least one substrate isseparated from at least one other light-transmissive portion of theplurality of light-transmissive portions of the at least one substrateby a gap that: (i) has a width and a depth, (ii) is partially filledwith a light segregation element of the plurality of light segregationelements, and (iii) is partially filled with at least onelight-transmissive material defining an inter-pixel light spreadingregion of the plurality of inter-pixel light spreading regions.

In certain embodiments, the gap includes a first portion of the widththat is filled with the light segregation element, and includes a secondportion of the width that is filled with the at least onelight-transmissive material. In certain embodiments, the gap includes afirst portion of the depth that is filled with the light segregationelement, and includes a second portion of the depth that is filled withthe at least one light-transmissive material. In certain embodiments,the solid state light emitting device further includes at least onelight-transmissive material region that is elevated relative to asurface of the at least one substrate and that is at least partiallyregistered with at least one of the light segregation element or theinter-pixel light spreading region.

In certain embodiments, each light-transmissive portion of the pluralityof light-transmissive portions of the at least one substrate comprisesat least one beveled edge forming an inter-pixel light spreading regionof the plurality of inter-pixel light spreading regions. In certainembodiments, the at least one substrate includes at least one lightextraction surface including the at least one beveled edge, and at leastone lumiphoric material arranged on or over the at least one lightextraction surface, wherein the at least one lumiphoric material isconfigured to receive at least a portion of the LED emissions andresponsively generate lumiphor emissions.

In certain embodiments, the solid state light emitting device furtherincludes a light-transmissive secondary substrate arranged over the atleast one substrate; and a lumiphoric material arranged between thelight-transmissive secondary substrate and the at least one substrate,wherein the lumiphoric material is configured to receive at least aportion of the LED emissions and responsively generate lumiphoremissions.

In certain embodiments, the solid state light emitting device furtherincludes a light scattering layer arranged on the light-transmissivesecondary substrate. In certain embodiments, the light-transmissivesecondary substrate is arranged between the lumiphoric material and thelight scattering layer.

In certain embodiments, the light-transmissive secondary substratecomprises a sapphire wafer.

In certain embodiments, the plurality of inter-pixel light spreadingregions is arranged at least partially within the light-transmissivesecondary substrate.

In certain embodiments, the plurality of inter-pixel light spreadingregions comprises a plurality of light redirecting regions within thelight-transmissive secondary substrate. In certain embodiments, theplurality of light redirecting regions comprises a plurality of voidsdefined within the light-transmissive secondary substrate. In certainembodiments, each light redirecting region of the plurality of lightredirecting regions comprises a further light-transmissive material thatdiffers in composition from a material of the light-transmissivesecondary substrate.

In certain embodiments, each light redirecting region of the pluralityof light redirecting regions comprises a rectangular cross-sectionalshape.

In certain embodiments, each light redirecting region of the pluralityof light redirecting regions comprises a triangular cross-sectionalshape, the triangular cross-sectional shape includes an apex and a base,and the apex is closer than the base to the at least one substrate. Incertain embodiments, each light redirecting region of the plurality oflight redirecting regions comprises a triangular cross-sectional shape,the triangular cross-sectional shape includes an apex and a base, andthe base is closer than the apex to the at least one substrate. Incertain embodiments, multiple layers, adjacent layers, multiplesubstrates, and/or adjacent substrates may contain the same structuresor different structures that form portions of overall light redirectingand/or light segregating features having the features described herein.

In certain embodiments, the at least one substrate comprises a pluralityof substrates, and each LED of the array of LEDs is joined to adifferent substrate of the plurality of substrates.

In certain embodiments, the at least one substrate consists of a single,continuous substrate supporting each LED of the array of LEDs.

In certain embodiments, the array of LEDs comprises a plurality of flipchip LEDs.

In another aspect, a solid state light emitting device, optionallyembodied in or incorporating a LED array chip, includes: an array ofLEDs arranged to transmit LED emissions through a plurality oflight-transmissive portions of at least one substrate; a plurality oflight segregation elements arranged at least partially within the atleast one substrate, wherein light segregation elements of the pluralityof light segregation elements are arranged between differentlight-transmissive portions of the plurality of light-transmissiveportions, the plurality of light segregation elements is configured toreduce passage of LED emissions between the different light-transmissiveportions; a light-transmissive secondary substrate arranged over the atleast one substrate; a lumiphoric material arranged between thelight-transmissive secondary substrate and the at least one substrate,wherein the lumiphoric material is configured to receive at least aportion of the LED emissions and responsively generate lumiphoremissions; and a plurality of light redirecting regions arranged atleast partially within the light-transmissive secondary substrate,wherein each light redirecting region of the plurality of lightredirecting regions is configured to enhance illumination of lightemitting surface portions of the solid state light emitting device thatare overlying and registered with the plurality of light segregationelements.

In certain embodiments, the plurality of light segregation elementscomprises at least one light-reflective or light-absorptive material.

In certain embodiments, the solid state light emitting device furtherincludes a light scattering layer arranged on the light-transmissivesecondary substrate. In certain embodiments, the light-transmissivesecondary substrate is arranged between the lumiphoric material and thelight scattering layer.

In certain embodiments, a portion of each light redirecting regionextends into or through a lumiphoric material layer containing thelumiphoric material.

In certain embodiments, the light-transmissive secondary substratecomprises a sapphire wafer.

In certain embodiments, the plurality of light redirecting regionscomprises a plurality of voids defined within the light-transmissivesecondary substrate.

In certain embodiments, each light redirecting region of the pluralityof light redirecting regions comprises a further light-transmissivematerial that differs in composition from a material of thelight-transmissive secondary substrate.

In certain embodiments, each light redirecting region of the pluralityof light redirecting regions comprises a rectangular cross-sectionalshape.

In certain embodiments, each light redirecting region of the pluralityof light redirecting regions comprises a triangular cross-sectionalshape, the triangular cross-sectional shape includes an apex and a base,and the apex is closer than the base to the at least one substrate. Incertain embodiments, each light redirecting region of the plurality oflight redirecting regions comprises a triangular cross-sectional shape,the triangular cross-sectional shape includes an apex and a base, andthe base is closer than the apex to the at least one substrate.

In certain embodiments, the at least one substrate comprises a pluralityof substrates, and each LED of the array of LEDs is joined to adifferent substrate of the plurality of substrates.

In certain embodiments, the at least one substrate consists of a single,continuous substrate supporting each LED of the array of LEDs.

In certain embodiments, the plurality of light segregation elementscomprises a plurality of unfilled voids defined in the at least onesubstrate.

In certain embodiments, the at least one substrate includes a pluralityof anode-cathode pairs in conductive electrical communication with thearray of LEDS; and the at least one substrate is mounted over a carriersubstrate or submount that includes a plurality of electrode pairs,wherein the plurality of anode-cathode pairs is in conductive electricalcommunication with the plurality of electrode pairs.

In another aspect, a method for fabricating a solid state light emittingdevice (optionally embodied in or incorporating a LED array chip)comprises: defining a plurality of recesses or grooves in at least onesubstrate supporting an array of LEDs, wherein recesses or grooves ofthe plurality of recesses or grooves are arranged generally between LEDsof the array of LEDs, and the at least one substrate includes aplurality of anode-cathode pairs in conductive electrical communicationwith the array of LEDs; mounting the at least one substrate over acarrier substrate or submount that includes a plurality of electrodepairs, wherein the mounting comprises establishing electricallyconductive paths between the plurality of anode-cathode pairs and theplurality of electrode pairs; thinning the at least one substrate aftersaid mounting of the at least one substrate over the carrier substrateor submount; and applying at least one lumiphoric material over the atleast one substrate, wherein the at least one lumiphoric material isconfigured to receive at least a portion of emissions of the array ofLEDs and responsively generate lumiphor emissions.

In certain embodiments, the array of LEDs is arranged to transmit LEDemissions through a plurality of light-transmissive portions of the atleast one substrate; and the method further comprises forming aplurality of light segregation elements in the at least one substrateconfigured to reduce passage of LED emissions between differentlight-transmissive portions of the plurality of light-transmissiveportions.

In certain embodiments, the forming of the plurality of lightsegregation elements comprises adding at least one light reflectivematerial to the plurality of grooves or recesses. In certainembodiments, the forming of the plurality of light segregation elementscomprises forming a plurality of unfilled voids within the plurality ofgrooves or recesses. In certain embodiments, the forming of theplurality of unfilled voids comprises: depositing a removable materialinto the plurality of grooves or recesses; and after said applying of atleast one lumiphoric material over the at least one substrate, removingthe removable material from the plurality of grooves or recesses toyield the plurality of unfilled voids. In certain embodiments, theremoving of the removable material from the plurality of grooves orrecesses comprises removal by at least one of chemical, mechanical, orthermal means.

In certain embodiments, the plurality of light-transmissive portions isconfigured to be illuminated by the array of LEDs to define a pluralityof pixels that includes a plurality of border portions, wherein eachpixel of the plurality of pixels includes at least one border portion ofthe plurality of border portions; and the method further comprisesforming a plurality of inter-pixel light spreading regions configured totransmit light through border portions of the plurality of borderportions to enhance inter-pixel illumination at light-emitting surfaceportions of the solid state light emitting device that are registeredwith or proximate to the plurality of light segregation elements. Incertain embodiments, the forming of the plurality of inter-pixel lightspreading regions comprises forming beveled edge portions of the atleast one substrate adjacent to the plurality of grooves or recesses.

In certain embodiments, the carrier substrate or submount comprises asemiconductor wafer, and the plurality of electrode pairs is arrangedin, on, or over the semiconductor wafer. In certain embodiments, thecarrier substrate or submount comprises at least one circuit configuredto control operation of the array of LEDs.

In another aspect, a solid state light emitting device, optionallyembodied in or incorporating a LED array chip, comprises: an array ofLEDs supported by at least one substrate; a plurality of lightsegregation elements arranged between different LEDs of the array ofLEDs; a plurality of anode-cathode pairs supported by the at least onesubstrate and in conductive electrical communication with the array ofLEDs; and a carrier substrate or submount comprising a semiconductorwafer and a plurality of electrode pairs arranged in, on, or over thesemiconductor wafer; wherein the plurality of anode-cathode pairs is inconductive electrical communication with the plurality of electrodepairs.

In certain embodiments, the array of LEDs is arranged to transmit LEDemissions through a plurality of light-transmissive portions of the atleast one substrate. In certain embodiments, the array of LEDs comprisesa plurality of flip chip LEDs. In certain embodiments, the at least onesubstrate consists of a single, continuous substrate supporting each LEDof the array of LEDs.

In certain embodiments, each anode of the plurality of anode-cathodepairs comprises a height that differs from each cathode of the pluralityof anode-cathode pairs. In certain embodiments, the carrier substrate orsubmount comprises at least one circuit configured to control operationof the array of LEDs.

In another aspect, the disclosure relates to a method for fabricating amulti-emitter solid state lighting device, the method comprising:mounting a multi-LED chip over an interface element comprising aplurality of electrode pairs, wherein the multi-LED chip comprises anarray of LEDs supported by a substrate and comprises a plurality ofanode-cathode pairs arranged between the substrate and the interfaceelement, and said mounting comprises establishing electricallyconductive paths between the plurality of anode-cathode pairs and theplurality of electrode pairs; and following said mounting, forming oneor more items of the following items (i) to (iv) on, in, or over thesubstrate: (i) a plurality of light-affecting elements, (ii) a pluralityof light processing elements, (iii) a plurality of light segregationelements, or (iv) a plurality of light steering structures.

In certain embodiments, the method further comprises applying at leastone lumiphoric material over the substrate, wherein the at least onelumiphoric material is configured to receive at least a portion ofemissions of the array of LEDs and responsively generate lumiphoremissions. In certain embodiments, the method further comprisesproviding an underfill material between the substrate and the interfaceelement. In certain embodiments, the interface element comprises acarrier substrate, or comprises an ASIC.

In certain embodiments, the forming of one or more items comprisesforming a plurality of light segregation elements at least partiallywithin the substrate, wherein the forming of a plurality of lightsegregation elements at least partially within the substrate comprisesdefining a plurality of recesses or grooves in the substrate. In certainembodiments, the method further comprises depositing at least onelight-affecting material within the plurality of recesses or grooves.

In certain embodiments, the method further comprises thinning thesubstrate following said mounting. In certain embodiments, the interfaceelement comprises a semiconductor wafer.

In another aspect, the disclosure relates to a method for fabricating amulti-emitter solid state lighting device comprising a multi-LED chipincorporating an array of LEDs supported by a substrate, the methodcomprising: selectively removing portions of epitaxial layers of themulti-LED chip (e.g., via etching, or alternatively via sawing or othercutting methods) to segregate active regions of LEDs of the array ofLEDs; and following said removing of portions of epitaxial layers,mounting the multi-LED chip over an interface element comprising aplurality of electrode pairs, wherein the multi-LED chip comprises aplurality of anode-cathode pairs arranged between the substrate and theinterface element, and said mounting comprises establishing electricallyconductive paths between the plurality of anode-cathode pairs and theplurality of electrode pairs.

In certain embodiments, the method further comprises, after saidmounting, forming one or more items of the following items (i) to (iv)on, in, or over the substrate: (i) a plurality of light-affectingelements, (ii) a plurality of light processing elements, (iii) aplurality of light segregation elements, or (iv) a plurality of lightsteering structures.

In certain embodiments, the method further comprises applying at leastone lumiphoric material over the substrate, wherein the at least onelumiphoric material is configured to receive at least a portion ofemissions of the array of LEDs and responsively generate lumiphoremissions. In certain embodiments, the method further comprisesproviding an underfill material between the substrate and the interfaceelement. In certain embodiments, the interface element comprises acarrier substrate or an ASIC.

In certain embodiments, the method further comprises defining aplurality of recesses or grooves in the substrate, wherein at least somerecesses or grooves of the plurality of recesses or grooves aresubstantially registered with regions of the multi-LED chip in whichportions of the epitaxial layers were selectively removed. In certainembodiments, the at least some recesses or grooves extend through anentire thickness of the substrate. In other embodiments, the at leastsome recesses or grooves extend through less than an entire thickness ofthe substrate (e.g., leaving a thin web or membrane of substratematerial adjacent to regions in which the epitaxial layers wereselectively removed). In certain embodiments, the method furthercomprises depositing at least one light-affecting material within theplurality of recesses or grooves. In certain embodiments, the methodfurther comprises thinning the substrate following said mounting. Incertain embodiments, the interface element comprises a semiconductorwafer.

In another aspect, any of the foregoing aspects, and/or various separateaspects and features as described herein, may be combined for additionaladvantage. Any of the various features and elements as disclosed hereinmay be combined with one or more other disclosed features and elementsunless indicated to the contrary herein.

Other aspects, features and embodiments of the present disclosure willbe more fully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional illustration of a single flip chip LEDincluding a light-transmissive surface that is patterned proximate tosemiconductor layers of the LED, including a multi-layer reflectorproximate to the semiconductor layers, and including a passivation layerbetween the multi-layer reflector and electrical contacts of the LED,with the single LED being representative of flip chips useable in flipchip LED arrays according to embodiments of the present disclosure.

FIG. 2A is a plan view photograph of a flip chip LED, with a transparentsubstrate facing upward, useable in flip chip arrays according toembodiments of the present disclosure.

FIG. 2B is a plan view photograph of the flip chip LED of FIG. 2A, withelectrodes facing upward.

FIG. 3A is a plan view photograph of a multi-LED chip including an arrayof four flip chip type LEDs on a single transparent substrate facingupward, useable in embodiments of the present disclosure.

FIG. 3B is a plan view photograph of the multi-LED chip of FIG. 3A, withelectrodes facing upward.

FIG. 4A is a plan view photograph of a multi-LED chip including an arrayof one hundred flip chip LEDs on a single transparent substrate facingupward, useable in embodiments of the present disclosure.

FIG. 4B is a plan view photograph of the multi-LED chip of FIG. 4A, withelectrodes facing upward.

FIGS. 5A-5C are plan view illustrations of a multi-LED chip including anarray of sixteen flip chip LEDs on a single transparent substrate facingupward in various states of fabrication, to define grooves or recessesbetween flip chip LEDs to enable formation of light segregation elementsextending from a light extraction surface into an interior of thesubstrate and to deposit a lumiphoric material on the light extractionsurface, according to certain embodiments of the present disclosure.

FIG. 5D is a plan view illustration of a transparent substrate facingdownward following formation of light segregation elements therein.

FIG. 5E is a plan view illustration of a multi-LED chip including anarray of sixteen flip chip LEDs formed on the substrate of FIG. 5Dbetween the light segregation elements, according to certain embodimentsof the present disclosure.

FIGS. 6A-6C are side cross-sectional view illustrations of the multi-LEDchip of FIGS. 5A-5C with a single transparent substrate facing downwardin various states of fabrication, to form light segregation elementsextending from a light extraction surface of the substrate into aninterior of the substrate and to deposit a lumiphoric material on thelight extraction surface, according to an embodiment of the presentdisclosure.

FIG. 7A is a side cross-sectional view illustration of a light emittingdevice (e.g., a multi-LED chip) including an array of flip chip LEDs ona single transparent substrate facing downward, including lightsegregation elements extending from a light injection surface into aninterior of the substrate, and including a lumiphoric material arrangedon the light extraction surface, according to an embodiment of thepresent disclosure.

FIG. 7B is a side cross-sectional view illustration of a light emittingdevice (e.g., a multi-LED chip) including an array of flip chip LEDs ona single transparent substrate facing downward, including lightsegregation elements extending from a textured light extraction surfaceinto an interior of the substrate, and including a lumiphoric materialarranged on the light extraction surface, according to an embodiment ofthe present disclosure.

FIG. 7C is a side cross-sectional view illustration of a light emittingdevice (e.g., a multi-LED chip) including an array of flip chip LEDs ona single transparent substrate facing downward, a first group of lightsegregation elements extending from a light injection surface of thesubstrate into an interior of the substrate, a second group of lightsegregation elements extending from a light extraction surface of thesubstrate into an interior of the substrate, and a lumiphoric materialarranged on the light extraction surface, according to an embodiment ofthe present disclosure.

FIGS. 8A-8D are side cross-sectional view illustrations of a lightemitting device (e.g., a multi-LED chip) including an array of flip chipLEDs on a single transparent substrate facing downward, including lightsegregation elements extending from a light extraction surface of thesubstrate into an interior of the substrate, with the device in variousstates of fabrication to: form light extraction recesses in the lightextraction surface, deposit one or more lumiphoric materials in thelight extraction recesses, and form lenses over the one or morelumiphoric materials deposited in the light extraction recesses,according to an embodiment of the present disclosure.

FIGS. 9A-9C are side cross-sectional view illustrations of a lightemitting device (e.g., a multi-LED chip) including an array of flip chipLEDs on a single transparent substrate facing downward, a first group oflight segregation elements extending from a light injection surface ofthe substrate into an interior of the substrate, and a second group oflight segregation elements extending from a light extraction surface ofthe substrate into an interior of the substrate, with the device invarious states of fabrication to: form raised features on the lightextraction surface, deposit one or more lumiphoric materials between theraised features, and form lenses over the one or lumiphoric materialsdeposited in the light extraction recesses, according to an embodimentof the present disclosure.

FIGS. 10A-10C are side cross-sectional view illustrations of a lightemitting device (e.g., a multi-LED chip) including an array of flip chipLEDs on a single transparent substrate including a first group of lightsegregation elements extending from a light injection surface of thesubstrate into an interior of the substrate, and a second group of lightsegregation elements extending from a light extraction surface of thesubstrate into an interior of the substrate, with the array in variousstates of fabrication to: form raised features on the light extractionsurface, deposit one or more lumiphoric materials between the raisedfeatures, and form lenses over the one or lumiphoric materials,according to an embodiment of the present disclosure.

FIG. 11A is a side cross-sectional exploded view illustration of themulti-LED chip of FIG. 6C arranged proximate to an interface element(optionally embodied in an application specific integrated circuit(ASIC) or carrier substrate or submount) and solder bumps.

FIG. 11B is a side cross-sectional view of the multi-LED chip andinterface element of FIG. 11A following completion of a solder bumpbonding process and addition of an underfill material between themulti-LED chip and the interface element.

FIG. 12A is a plan view illustration of a light emitting device (e.g., amulti-LED chip) including an array of sixteen flip chip LEDs on a singletransparent substrate with electrodes facing upward.

FIG. 12B is a plan view illustration of a lower layer of an electricalinterface for the light emitting device of FIG. 12A, with multiplehorizontal string series connections each including multipleelectrically conductive vias for coupling with anodes of the lightemitting device, and with the lower layer further including openingspermitting passage of conductive vias defined in an upper layer of theelectrical interface.

FIG. 12C is a plan view illustration of an upper layer of an electricalinterface for the light emitting device of FIG. 12A, with multiplevertical string series connections each including multiple electricallyconductive vias for coupling with cathodes of the light emitting device,

FIG. 12D is a plan view illustration of the upper layer of FIG. 12Csuperimposed over the lower layer of FIG. 12B to form an electricalinterface for the light emitting device of FIG. 12A.

FIG. 12E is a plan view illustration of the electrical interface of FIG.12D coupled with the light emitting device of FIG. 12A.

FIG. 13A is a plan view illustration of a light emitting device (e.g., amulti-LED chip) including an array of sixteen flip chip LEDs on a singletransparent substrate with electrodes facing upward.

FIG. 13B is a plan view illustration of a lower layer of an electricalinterface for the light emitting device of FIG. 13A, with multiplehorizontal string series connections each including multipleelectrically conductive vias for coupling with anodes of the lightemitting device, and with the lower layer further including openingspermitting passage of conductive vias defined in an upper layer of theelectrical interface.

FIG. 13C is a plan view illustration of an upper layer of an electricalinterface for the light emitting device of FIG. 13A, with multiplevertically arranged parallel connections each including multipleelectrically conductive vias for coupling with cathodes of the lightemitting device.

FIG. 13D is a plan view illustration of the upper layer of FIG. 13Csuperimposed over the lower layer of FIG. 13B to form an electricalinterface for the light emitting device of FIG. 13A.

FIG. 13E is a plan view illustration of the electrical interface of FIG.13D coupled with the light emitting device of FIG. 13A, according to anembodiment of the present disclosure.

FIG. 14A is a plan view diagram of an addressable multi-LED lightemitting device (e.g., a multi-LED chip) configured to produce a firstcombination of colors, according to an embodiment of the presentdisclosure.

FIG. 14B is a plan view diagram of an addressable multi-LED lightemitting device (e.g., a multi-LED chip) configured to produce a secondcombination of colors, according to an embodiment of the presentdisclosure.

FIG. 14C is a plan view diagram of an addressable multi-LED lightemitting device (e.g., a multi-LED chip) configured to produce a thirdcombination of colors, according to an embodiment of the presentdisclosure.

FIG. 14D is a plan view diagram of an addressable multi-LED lightemitting device (e.g., a multi-LED chip) configured to produce a fourthcombination of colors, according to an embodiment of the presentdisclosure.

FIG. 15 is a simplified schematic diagram showing interconnectionsbetween components of a light emitting device including two emitterarrays (e.g., optionally embodied in two multi-LED chips) each includingindividually addressable flip chip LEDs.

FIG. 16 is a side cross-sectional view illustration of a light emittingdevice including an array of flip chip LEDs on a single transparentsubstrate facing downward and joined to a carrier, with a first group oflight segregation elements extending from a light injection surface ofthe substrate into an interior of the substrate, a second group of lightsegregation elements extending from a light extraction surface of thecarrier into an interior of the carrier, and a lumiphoric materialarranged on the light extraction surface of the carrier, according to anembodiment of the present disclosure.

FIG. 17 is a side cross-sectional view illustration of a light emittingdevice including a first array of flip chip LEDs on a first transparentsubstrate (e.g., embodied in a first multi-LED chip) and a second arrayof flip chip LEDs on a second transparent substrate (e.g., embodied in asecond multi-LED chip) both joined to a carrier, wherein each substrateincludes a first group of light segregation elements extending from alight injection surface of the substrate into an interior of thesubstrate and a second group of light segregation elements extendingfrom a light extraction surface of the substrate into an interior of thesubstrate, the carrier includes another group of light segregationelements extending from a light injection surface of the carrier into aninterior of the carrier, and a lumiphoric material is arranged on atextured or patterned light extraction surface of the carrier, accordingto an embodiment of the present disclosure.

FIG. 18 is a side cross-sectional view illustration of a light emittingdevice including a first array of flip chip LEDs on a first transparentsubstrate (e.g., embodied in a first multi-LED chip) and a second arrayof flip chip LEDs on a second transparent substrate (e.g., embodied in asecond multi-LED chip), a lumiphoric material layer arranged in contactwith a light extraction surface of each substrate, and a carrierarranged to support the lumiphoric material layer and each substrate,wherein each substrate includes a first group of light segregationelements extending from a light injection surface of the substrate intoan interior of the substrate and a second group of light segregationelements extending from a light extraction surface of the substrate intoan interior of the substrate, the carrier includes another group oflight segregation elements extending from a light injection surface ofthe carrier into an interior of the carrier, and the carrier includes atextured or patterned light extraction surface, according to anembodiment of the present disclosure.

FIG. 19 is a top plan view of a light emitting device including acarrier supporting four individually addressable arrays of lightemitting devices (e.g., embodied in four multi-LED chips) each includinglight segregation elements between individual LEDs, according to anembodiment of the present disclosure.

FIG. 20A is a top plan view digital photograph of a light emittingdevice (e.g., a multi-LED chip) including an array of sixteen LEDs(e.g., sixteen pixels) with light segregation elements betweenindividual LEDs forming a dark grid, and with each LED shown in anon-illuminated state.

FIG. 20B is a top plan view digital photograph of the light emittingdevice of FIG. 20A with current supplied to the rightmost column of fourLEDs, showing the rightmost column of four LEDs being illuminated,showing an adjacent column of LEDs being partially illuminated due tospillover of light from the rightmost column of LEDs, and showingnon-illuminated or “dark” zones between adjacent illuminated LEDs.

FIG. 20C is a color inverted version of the digital photograph of FIG.20B.

FIG. 21A is a top view intensity mapped image of an eight-pixel portionof a light emitting device (e.g., a multi-LED chip) including an arrayof multiple LEDs, showing a leftmost column of four LEDs beingilluminated, showing an adjacent column of four LEDs being partiallyilluminated due to spillover of light from the leftmost column of LEDs,and showing non-illuminated or “dark” zones between adjacent illuminatedLEDs.

FIG. 21B includes four overlaid plots of relative light intensity(percent) versus position (millimeters) for the leftmost column of fourilluminated LEDs of FIG. 21A.

FIG. 22A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) duringfabrication including two LEDs following formation of a recess or groovein at least a portion of a substrate.

FIG. 22B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 22A following sequential additionof a light segregation element and a light-transmissive material in therecess or groove, with the light-transmissive material serving toenhance inter-pixel illumination at a light emitting surface of thesolid state light emitting device to reduce appearance ofnon-illuminated or “dark” regions between the LEDs when they areilluminated.

FIG. 22C is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 22B following application of alumiphoric material over the substrate and over the light-transmissivematerial within the recess or groove.

FIG. 23A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) includingmultiple LEDs and a substrate, with a recess or groove in at least aportion of the substrate that is sequentially filled with a lightsegregation element and a light-transmissive material, with alight-transmissive material region that is elevated relative to asurface of the substrate, and with a lumiphoric material arranged overthe substrate and the elevated light-transmissive material region.

FIG. 23B is a top plan view of at least a portion of the solid statelight emitting device portion of FIG. 23A including four LEDs, withdashed lines depicting the elevated light-transmissive material region.

FIG. 24A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) includingmultiple LEDs and a substrate during fabrication, with substrateportions including excess thickness and including a recess or groovethat is sequentially filled with a first material providing lightsegregation utility and a second material providing light spreading orlight redirecting utility, and with a carrier substrate or submounthaving multiple electrode pairs positioned below, but not in contactwith, anode-cathode pairs of the solid state light emitting device.

FIG. 24B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 24A, following mounting of theanode-cathode pairs to electrode pairs of the carrier substrate orsubmount, thinning of the substrate and materials embedded therein, andformation of a lumiphoric material layer over the substrate.

FIG. 25A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) includingmultiple LEDs and a substrate during fabrication, with substrateportions including excess thickness and including a recess or groovethat is filled with a removable (e.g., sacrificial) material, withmultiple anode-cathode pairs mounted in conductive electricalcommunication with multiple electrode pairs of an interface element(e.g., ASIC, or carrier substrate or submount), and with an underfillmaterial arranged between the multi-LED chip and the interface element.

FIG. 25B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 25A, following thinning of thesubstrate and the removable material embedded therein.

FIG. 25C is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 25B, following formation of alumiphoric material layer over the substrate.

FIG. 25D is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 25C, following removal of theremovable material from the substrate.

FIG. 26A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) includingmultiple LEDs and a substrate mounted over an interface element (e.g.,ASIC, or carrier substrate or submount), with an unfilled recess orgroove defined in the substrate, an adhesion promoting material arrangedover the substrate, a lumiphoric material film arranged over thesubstrate and the adhesion promoting material, and with an underfillmaterial arranged between the multi-LED chip and the interface element.

FIG. 26B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 26A following adhesion of thelumiphoric material film over the substrate, with the recess or groovearranged between the LEDs remaining unfilled.

FIG. 27A is a side cross-sectional view of a portion of a solid statelight emitting device (e.g., a multi-LED chip) including three LEDs anda substrate following performance of certain fabrication steps, withrecesses or grooves being defined in portions of the substrate betweenadjacent LEDs, and with a first portion of a width of each recess orgroove being filled with a light segregation element.

FIG. 27B is a side cross-sectional view of the portion of the solidstate light emitting device of FIG. 27A, following addition of at leastone light-transmissive material to fill a second portion of the width ofeach recess or groove, with the at least one light-transmissive materialbeing in contact with the light segregation element in each recess orgroove.

FIG. 28A is a side cross-sectional view of three LEDs, each including asubstrate portion and being mounted along a first lateral surfacethereof to a carrier.

FIG. 28B is a side cross-sectional view of the three LEDs and carrier ofFIG. 28A following formation of at least one light-affecting element ona second lateral surface of each LED and corresponding substrateportion.

FIG. 28C is a side cross-sectional view of a portion of a solid statelight emitting device incorporating the LEDs of FIG. 28B followingmounting of the three LEDs to a carrier substrate or submount, andfollowing formation of a light-transmissive material between lateralsurfaces of adjacent LEDs.

FIG. 28D is a side cross-sectional view of the solid state lightemitting device portion of FIG. 28C following application of alumiphoric material over the substrate portion of each LED and over theat least one light-affecting element and light-transmissive materialbetween adjacent LEDs.

FIG. 29A is a side cross-sectional view of a portion of a solid statelight emitting device (e.g., a multi-LED chip) including two LEDs and asubstrate defining a recess or groove containing a light segregationelement, and with the substrate including beveled edge portions arrangedproximate to the light segregation element.

FIG. 29B is a side cross-sectional view of the solid state lightemitting device portion of FIG. 29A following application of alumiphoric material over the substrate, the beveled edge portions, andthe light segregation element, with the beveled edge portions serving toenhance inter-pixel illumination at a light emitting surface of thesolid state light emitting device to reduce appearance ofnon-illuminated or “dark” regions between the LEDs when they areilluminated.

FIG. 30A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) includingmultiple LEDs and a substrate mounted over an interface element (e.g.,ASIC, or carrier substrate or submount), with an unfilled recess orgroove defined in the substrate, beveled edge portions of the substrateproximate to the recess or groove, and an underfill material arrangedbetween the multi-LED chip and the interface element.

FIG. 30B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 30A, following addition of anadhesion promoting material over the substrate, and adhesion of alumiphoric material film over the adhesion promoting material.

FIG. 31 is a side cross-sectional view of a portion of a solid statelight emitting device including three LEDs and a substrate (e.g., amulti-LED chip), with recesses or grooves being defined in portions ofthe substrate between adjacent LEDs, each recess or groove being filledwith a light segregation element, a lumiphoric material layer arrangedover the substrate and the light segregation elements, a secondarysubstrate arranged over the lumiphoric material layer and includingtriangular light redirecting regions therein proximate to the lumiphoricmaterial layer, and a light scattering material arranged over thesecondary substrate.

FIG. 32 is a side cross-sectional view of a portion of a solid statelight emitting device including three LEDs and a substrate (e.g., amulti-LED chip), with recesses or grooves being defined in portions ofthe substrate between adjacent LEDs, each recess or groove being filledwith a light segregation element, a lumiphoric material film layerarranged over the substrate, a secondary substrate arranged over thelumiphoric material film layer and including rectangle-shaped lightredirecting regions in the secondary substrate and extending through thelumiphoric material film layer, and a light scattering material arrangedover the secondary substrate, with the light redirecting regions beingsubstantially the same width as the light segregation elements.

FIG. 33 is a side cross-sectional view of a portion of a solid statelight emitting device including three LEDs and a substrate (e.g., amulti-LED chip), with recesses or grooves being defined in portions ofthe substrate between adjacent LEDs, each recess or groove being filledwith a light segregation element, a lumiphoric material layer arrangedover the substrate and the light segregation elements, a secondarysubstrate arranged over the lumiphoric material layer and includingtriangular light redirecting regions therein, and a light scatteringmaterial arranged over the secondary substrate, with the triangularlight redirecting regions each including a base portion extendingthrough the light scattering material.

FIG. 34 is a side cross-sectional view of a portion of a solid statelight emitting device including three LEDs and a substrate (e.g., amulti-LED chip), with recesses or grooves being defined in portions ofthe substrate between adjacent LEDs, each recess or groove being filledwith a light segregation element that extends beyond the substrate, alumiphoric material layer arranged over the substrate between the lightsegregation elements, a secondary substrate arranged over the lumiphoricmaterial layer and including triangular light redirecting regionstherein, and a light scattering material arranged over the secondarysubstrate, with the triangular light redirecting regions each includinga base portion extending through the light scattering material.

FIG. 35 is a side cross-sectional view of a portion of a solid statelight emitting device including three LEDs and a substrate (e.g., amulti-LED chip), with recesses or grooves being defined in portions ofthe substrate between adjacent LEDs, each recess or groove being filledwith a light segregation element, a lumiphoric material layer arrangedover the substrate, a secondary substrate arranged over the lumiphoricmaterial layer and including rectangle-shaped light redirecting regionsin the secondary substrate and extending through the lumiphoric materiallayer, and a light scattering material arranged over the secondarysubstrate, with the light redirecting regions being narrower in widththan the light segregation elements.

FIG. 36 is a top plan view of interconnections between a circuit boardand a carrier substrate or submount of a test apparatus for operating asolid state light emitting device including a high density LED array(e.g., embodying at least one multi-LED chip) as disclosed herein.

FIG. 37A is a top plan view of a carrier substrate or submount includinga semiconductor wafer supporting multiple electrical traces leading to arectangular array mounting area suitable for receiving a solid statelight emitting device (e.g., a multi-LED chip) including a high densityLED array and useable as part of a test apparatus.

FIG. 37B is a color inverted version of FIG. 37A.

FIG. 38A is a magnified portion of the carrier substrate or submount ofFIGS. 37A and 37B, and FIG. 38B is a color inverted version of FIG. 38A.

FIG. 39A is a side cross-sectional schematic assembly view of a portionof a solid state light emitting device including two flip chip LEDsassociated with a single substrate (e.g., optionally embodied in onemulti-LED chip), with anodes and cathodes having different heightsrelative to one another, and being arranged above (without contacting)electrodes of different heights provided along a top surface of acarrier substrate or submount.

FIG. 39B is a side cross-sectional schematic assembly view of a portionof a solid state light emitting device including two flip chip LEDsarranged over a single substrate (e.g., optionally embodied in onemulti-LED chip), with anodes and cathodes having different heightsrelative to one another, and being arranged above (without contacting)electrodes provided along a top surface of a carrier substrate orsubmount, with one electrode per electrode pair including boundary wallscontaining a solder bump material.

FIG. 40A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) includingmultiple LEDs and a substrate mounted over an interface element (e.g.,ASIC or carrier substrate or submount), prior to defining of a recess orgroove defined in a substrate connecting the LEDs.

FIG. 40B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 40A following formation of arecess or groove in the substrate.

FIG. 40C is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 40B following addition of aremovable (e.g., sacrificial) material to the recess or groove, andfollowing formation of a lumiphoric material layer over the substrateand the removable material.

FIG. 40D is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 40C following removal of theremovable material from the recess or groove.

FIG. 41 is a side cross-sectional schematic view of a solid state lightemitting device (e.g., a multi-LED chip) including multiple LEDs and asubstrate mounted over a first interface element embodied in a carriersubstrate or submount including electrical contacts arranged on firstand second major surfaces with electrically conductive vias arrangedtherebetween, and with the carrier substrate or submount positioned overa second interface element embodied in an ASIC to enable mounting of thecarrier substrate or submount between the multi-LED chip and the ASIC.

FIG. 42 is a side cross-sectional schematic view of two solid statelight emitting devices (e.g., multi-LED chips) mounted over a singleinterface element (e.g., ASIC, or carrier substrate or submount), priorto defining of recesses or grooves in substrates of the multi-LED chips.

FIG. 43 is a side cross-sectional schematic view of a single solid statelight emitting device (e.g., a multi-LED chip) mounted over multipleinterface elements (e.g., ASICs, or carrier substrates or submounts),prior to defining of recesses or grooves in a substrate connecting LEDsof the multi-LED chip.

FIG. 44A is a side cross-sectional schematic view of a portion of asolid state light emitting device (e.g., a multi-LED chip) including agroove or recess defined between epitaxial layers of different LEDs ofthe multi-LED chip.

FIG. 44B is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 44A after being mounted over aninterface element (e.g., ASIC, or carrier substrate or submount).

FIG. 44C is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 44B following addition of anunderfill material between the multi-LED chip and the interface element,and formation of a recess or groove in the substrate, with the recess orgroove extending through a majority but less than an entirety of thesubstrate.

FIG. 44D is a side cross-sectional schematic view of the solid statelight emitting device portion of FIG. 44B following addition of anunderfill material between the multi-LED chip and the interface element,and formation of a recess or groove in the substrate, with the recess orgroove extending through the entire thickness of the substrate to reachthe underfill material.

FIG. 45 is a side cross-sectional schematic view of a portion of a solidstate light emitting device (e.g., a multi-LED chip) including groovesor recesses defined between adjacent LEDs of the multi-LED chip, andwith different emitter regions having different characteristics.

DETAILED DESCRIPTION

The art continues to seek improved LED array devices with small pixelpitches while overcoming limitations associated with conventionaldevices and production methods. Various embodiments disclosed hereinrelate to solid state light emitting devices including at least onearray of LEDs supported by a substrate (optionally embodied in amulti-LED chip), preferably including one or more lumiphoric materialsarranged to receive emissions of at least some flip chip LEDs, andincluding light segregation elements configured to reduce interactionbetween emissions of different LEDs and/or lumiphoric material regionsto reduce scattering and/or optical crosstalk, thereby preservingpixel-like resolution of the resulting emissions. In certainembodiments, each LED of the array of LEDs is in a flip chipconfiguration. In certain embodiments, light segregation elements arearranged at least partially within the substrate supporting multipleLEDs, and are positioned between different light-transmissive regions ofthe substrate. In certain embodiments, light segregation elements arearranged on or over portions of a light extraction surface of asubstrate, and are generally registered with boundaries between LEDs.Absent the presence of light segregation elements, the omnidirectionalcharacter of LED and/or lumiphor emissions would detrimentally affectresolution (e.g., pixel resolution) of an array of LEDs with one or morelumiphoric materials supported by a single substrate. In certainembodiments, the LEDs define multiple pixels, and multiple inter-pixellight spreading regions are configured to transmit light through borderportions of the pixels to enhance inter-pixel illumination atlight-emitting surface portions that are registered with or proximate tothe light segregation elements. In certain embodiments, multiple lightredirecting regions are arranged at least partially within alight-transmissive secondary substrate overlying a lumiphoric materialthat is arranged over a substrate that includes light segregationelements, with the light redirecting regions being configured to enhanceillumination of light emitting surface portions of the solid state lightemitting device that are overlying and registered with the lightsegregation elements. The foregoing inter-pixel light spreading regionsand/or light redirecting regions are preferably configured to reduceappearance of non-illuminated or “dark” regions between the LEDs whenthey are illuminated. Solid state light emitting devices (e.g.,embodying or including multi-LED chips) including light segregationelements as disclosed herein may be used in various applications such assequentially illuminated LED displays, vehicular headlamps, roadwayillumination, light fixtures, and various indoor, outdoor, and specialtycontexts. Methods for fabricating solid state light emitting devicesdisclosed herein are also provided.

The embodiments set forth herein represent the necessary information toenable those skilled in the art to practice the embodiments andillustrate the best mode of practicing the embodiments. Upon reading thefollowing description in light of the accompanying drawing figures,those skilled in the art will understand the concepts of the disclosureand will recognize applications of these concepts not particularlyaddressed herein. It should be understood that these concepts andapplications fall within the scope of the disclosure and theaccompanying claims.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element such as a layer, region, orsubstrate is referred to as being “on” or extending “onto” anotherelement, it can be directly on or extend directly onto the other elementor intervening elements may also be present. In contrast, when anelement is referred to as being “directly on” or extending “directlyonto” another element, there are no intervening elements present.Likewise, it will be understood that when an element such as a layer,region, or substrate is referred to as being “over” or extending “over”another element, it can be directly over or extend directly over theother element, or intervening elements may also be present. In contrast,when an element is referred to as being “directly over” or extending“directly over” another element, there are no intervening elementspresent. It will also be understood that when an element is referred toas being “connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element, or intervening elements maybe present. In contrast, when an element is referred to as being“directly connected” or “directly coupled” to another element, there areno intervening elements present.

Relative terms such as “below,” “above,” “upper,” “lower,” “horizontal,”or “vertical” may be used herein to describe a relationship of oneelement, layer, or region to another element, layer, or region asillustrated in the Figures. It will be understood that these terms andthose discussed above are intended to encompass different orientationsof the device in addition to the orientation depicted in the Figures.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes,” and/or “including” when used herein specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms used herein should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthis specification and the relevant art and will not be interpreted inan idealized or overly formal sense unless expressly so defined herein.

As used herein, an “active region” of a solid state light emittingdevice refers to the region in which majority and minority electroniccarriers (e.g., holes and electrons) recombine to produce light. Ingeneral, an active region according to embodiments disclosed herein caninclude a double heterostructure or a well structure, such as a quantumwell structure.

Solid state light emitting devices disclosed herein may include at leastone solid state light source (e.g., a LED) and one or more lumiphoricmaterials (also referred to herein as lumiphors) arranged to receiveemissions of the at least one solid state light source. A lumiphoricmaterial may include one or more of a phosphor, a scintillator, alumiphoric ink, a quantum dot material, a day glow tape, or the like. Incertain embodiments, a lumiphoric material may be in the form of one ormore phosphors and/or quantum dots arranged in a binder such as siliconor glass, arranged in the form of a single crystalline plate or layer,arranged in the form of a polycrystalline plate or layer, and/orarranged in the form of a sintered plate. In certain embodiments, alumiphoric material such as a phosphor may be spin coated or sprayed ona surface of a LED array. In certain embodiments, a lumiphoric materialmay be located on a growth substrate, on epitaxial layers, and/or on acarrier substrate of a LED array. Multiple pixels including one or morelumiphoric materials may be manufactured in a single plate. In general,a solid state light source may generate light having a first dominantwavelength. At least one lumiphor receiving at least a portion of thelight generated by the solid state light source may re-emit light havinga second dominant wavelength that is different from the first dominantwavelength. A solid state light source and one or more lumiphoricmaterials may be selected such that their combined output results inlight with one or more desired characteristics such as color, colorpoint, intensity, etc. In certain embodiments, aggregate emissions ofone or more flip chip LEDs, optionally in combination with one or morelumiphoric materials, may be arranged to provide cool white, neutralwhite, or warm white light, such as within a color temperature range offrom 2500K to 10,000K. In certain embodiments, lumiphoric materialshaving cyan, green, amber, yellow, orange, and/or red dominantwavelengths may be used. In certain embodiments, lumiphoric materialsmay be added to one or more emitting surfaces (e.g., top surface and oneor more edge surfaces) by methods such as spray coating, dipping, liquiddispensation, powder coating, inkjet printing, or the like. In certainembodiments, lumiphoric material may be dispersed in an encapsulant,adhesive, or other binding medium.

As used herein, a layer or region of a light emitting device may beconsidered to be “transparent” when at least 90% of emitted radiationthat impinges on the transparent layer or region emerges through thetransparent region. Moreover, as used herein, a layer or region of anLED is considered to be “reflective” or embody a “reflector” when atleast 90% of the angle averaged emitted radiation that impinges on thelayer or region is reflected. For example, in the context of galliumnitride-based blue and/or green LEDs, silver (for example, at least 90%reflective) may be considered a reflective material. In the case ofultraviolet (UV) LEDs, appropriate materials may be selected to providea desired, and in some embodiments high, reflectivity and/or a desired,and in some embodiments low, absorption. In certain embodiments, a“light-transmissive” material may be configured to transmit at least 50%of emitted radiation of a desired wavelength.

Certain embodiments disclosed herein relate to the use of flip chip LEDdevices in which a light transmissive substrate represents the exposedlight emitting surface. In certain embodiments, the light transmissivesubstrate embodies or includes a LED growth substrate, wherein multipleLEDs are grown on the same substrate that forms a light emitting surfaceor region. In certain embodiments, a monolithic multi-LED chip includesLEDs that are all grown on the same growth substrate, with the LEDs alsosharing the same n-GaN layer and/or other functional layers. In certainembodiments, one or more portions (or the entirety) of a growthsubstrate and/or portions of epitaxial layers may be thinned or removed.In certain embodiments, a second substrate (also known as a carrier) maybe added to a multi-LED chip, whether or not a growth substrate has beenpartially or fully removed. In certain embodiments, a light transmissivesubstrate includes silicon carbide (SiC), sapphire, or glass. MultipleLEDs (e.g., flip chip LEDs) may be grown on a substrate and incorporatedinto a light emitting device. In certain embodiments, a substrate (e.g.,silicon) may include vias arranged to make contact with LED chipsmounted or grown thereon. In certain embodiments, as an alternative tousing flip chips, individual LEDs or LED packages may be individuallyplaced and mounted on or over a substrate to form an array. For example,multiple wafer level packaged LEDs may be used to form LED arrays orsubarrays.

When LEDs embodying a flip chip configuration are used, desirable flipchip LEDs incorporate multi-layer reflectors and incorporate lighttransmissive (preferably transparent) substrates patterned along aninternal surface adjacent to semiconductor layers. A flip chip LEDincludes anode and cathode contacts that are spaced apart and extendalong the same face, with such face opposing a face defined by the lighttransmissive (preferably transparent) substrate. A flip chip LED may betermed a horizontal structure, as opposed to a vertical structure havingcontacts on opposing faces of a LED chip. In certain embodiments, thetransparent substrate may be patterned, roughened, or otherwise texturedto provide a varying surface that increases the probability ofrefraction over internal reflection, so as to enhance light extraction.A substrate may be patterned or roughened by any of various methodsknown in the art, including (but not limited to) formation of nano-scalefeatures by etching (e.g., photolithographic etching) using any suitableetchants, optionally in combination with one or more masks.

Patterning or texturing of a substrate may depend on the substratematerial as well as implications on light extraction efficiency and/orpixel separation. If a silicon carbide substrate bearing multiple LEDs(e.g., flip chip LEDs) is used, then the index of refraction of thesilicon carbide is well-matched to a gallium nitride-based active regionof a LED, so light emissions of the active region tend to enter thesubstrate easily. If a sapphire substrate bearing multiple LEDs (e.g.,flip chip LEDs) is used, then it may be desirable to provide apatterned, roughened, or textured interface between the active regionand the substrate to promote passage of LED emissions into thesubstrate. With respect to a light extraction surface of a substrate, incertain embodiments it may be desirable to provide a patterned,roughened, or textured surface to promote extraction of light from thesubstrate.

In certain embodiments, LEDs may be grown on a first substrate of afirst material (e.g., silicon, silicon carbide or sapphire), the first(growth) substrate may be partially removed (e.g., thinned) or fullyremoved, and the LEDs may be bonded to, mounted to, or otherwisesupported by a second substrate of a second material (e.g., glass,sapphire, etc.) through which LED emissions are transmitted, wherein thesecond material is preferably more transmissive of LED emissions thanthe first material. Removal of the first (growth) substrate may be doneby any appropriate method, such as use of an internal parting region orparting layer that is weakened and/or separated by: application ofenergy (e.g., laser rastering, sonic waves, heat, etc.), fracturing, oneor more heating and cooling cycles, chemical removal, and/or mechanicalremoval (e.g., including one or more grinding, lapping, and/or polishingsteps), or by any appropriate combination of techniques. In certainembodiments, one or more substrates may be bonded or otherwise joined toa carrier. Bonding of one or more LEDs to a substrate, or bonding ofsubstrates to a carrier, may be performed by any suitable methods. Anysuitable wafer bonding technique known in the art may be used, such asmay rely on van der Waals bonds, hydrogen bonds, covalent bonds, and/ormechanical interlocking. In certain embodiments, direct bonding may beused. In certain embodiments, bonding may include one or more surfaceactivation steps (e.g., plasma treatment, chemical treatment, and/orother treatment methods) followed by application of heat and/orpressure, optionally followed by one or more annealing steps. In certainembodiments, one or more adhesion promoting materials may additionallyor alternatively be used.

In certain embodiments, a LED array is monolithic and includes multipleflip chip LEDs grown on a single first (or growth) substrate, with thegrowth substrate removed from the LEDs, and a second substrate (orcarrier) added to the LEDs, with the second substrate including one ormore reflective layers, vias, and a phosphor layer (e.g., spin-coatedphosphor layer). In certain embodiments, a LED array is monolithic andincludes multiple flip chip LEDs grown on a single growth substrate,wherein grooves, recesses, or other features are defined in the growthsubstrate and/or a carrier, and are used to form light-affectingelements, optionally being filled with one or more materials such as toform a grid between individual LEDs or pixels.

In certain embodiments utilizing flip chip LEDs (e.g., embodied in asingle multi-LED array), a light-transmissive substrate, a plurality ofsemiconductor layers, a multi-layer reflector, and a passivation layermay be provided. The light-transmissive substrate is preferablytransparent with a patterned surface including a plurality of recessedfeatures and/or a plurality of raised features. The plurality ofsemiconductor layers is adjacent to the patterned surface, and includesa first semiconductor layer comprising doping of a first type and asecond semiconductor layer comprising doping of a second type, wherein alight emitting active region is arranged between the first semiconductorlayer and the second semiconductor layer. A multi-layer reflectorarranged proximate to the plurality of semiconductor layers includes ametal reflector layer and a dielectric reflector layer, wherein thedielectric reflector layer is arranged between the metal reflector layerand the plurality of semiconductor layers. A passivation layer isarranged between the metal reflector layer and first and secondelectrical contacts, wherein the first electrical contact is arranged inconductive electrical communication with the first semiconductor layer,and the second electrical contact is arranged in conductive electricalcommunication with the second semiconductor layer. In certainembodiments, a first array of conductive microcontacts extends throughthe passivation layer and provides electrical communication between thefirst electrical contact and the first semiconductor layer, and a secondarray of conductive microcontacts extends through the passivation layer.In certain embodiments, a substrate useable for forming and supportingan array of flip chip LEDs may include sapphire; alternatively, thesubstrate may include silicon, silicon carbide, a Group III-nitridematerial (e.g., GaN), or any combination of the foregoing materials(e.g., silicon on sapphire, etc.). Further details regarding fabricationof flip chip LEDs are disclosed in U.S. Patent Application PublicationNo. 2017/0098746 A1, with the entire contents thereof being herebyincorporated by reference herein.

FIG. 1 illustrates a single flip chip LED 10 including a substrate 15,first and second electrical contacts 61, 62, and a functional stack 60arranged therebetween. The flip chip LED 10 includes an internallight-transmissive surface 14 that is patterned (with multiple recessedand/or raised features 17) proximate to semiconductor layers of the LED10, including a multi-layer reflector proximate to the semiconductorlayers according to one embodiment. The light transmissive (preferablytransparent) substrate 15 has an outer major surface 11, side edges 12,and the patterned surface 14. Multiple semiconductor layers 21, 22sandwiching a light emitting active region 25 are adjacent to thepatterned surface 14, and may be deposited via vapor phase epitaxy orany other suitable deposition process. In one implementation, a firstsemiconductor layer 21 proximate to the substrate 15 embodies an n-dopedmaterial (e.g., n-GaN), and the second semiconductor layer 22 embodies ap-doped material (e.g., p-GaN). A central portion of the multiplesemiconductor layers 21, 22 including the active region 25 extends in adirection away from the substrate 15 to form a mesa 29 that is laterallybounded by at least one recess 39 containing a passivation material(e.g., silicon nitride as part of a passivation layer 50), and that isvertically bounded by surface extensions 21A of the first semiconductorlayer 21.

A multi-layer reflector is arranged proximate to (e.g., on) the secondsemiconductor layer 22, with the multi-layer reflector consisting of adielectric reflector layer 40 and a metal reflector layer 42. Thedielectric reflector layer 40 is arranged between the metal reflectorlayer 42 and the second semiconductor layer 22. In certainimplementations, the dielectric reflector layer 40 comprises silicondioxide, and the metal reflector layer 42 comprises silver. Numerousconductive vias 41-1, 41-2 are defined in the dielectric reflector layer40 and are preferably arranged in contact between the secondsemiconductor layer 22 and the metal reflector layer 42. In certainimplementations, the conductive vias 41-1, 41-2 comprise substantiallythe same material(s) as the metal reflector layer 42. In certainimplementations, at least one (preferably both) of the dielectricreflector layer 40 and the metal reflector layer 42 is arranged oversubstantially the entirety of a major surface of the mesa 29 terminatedby the second semiconductor layer 22 (e.g., at least about 90%, at leastabout 92%, or at least about 95% of the major (e.g., lower) surface ofthe mesa portion of the second semiconductor layer 22).

A barrier layer 48 (including portions 48-1 and 48-2) is preferablyprovided between the metal reflector layer 42 and the passivation layer50. In certain implementations, the barrier layer 48 comprises sputteredTi/Pt followed by evaporated Au, or comprises sputtered Ti/Ni followedby evaporated Ti/Au. In certain implementations, the barrier layer 48may function to prevent migration of metal from the metal reflectorlayer 42. The passivation layer 50 is arranged between the barrier layer48 and (i) a first externally accessible electrical contact (orelectrode) 61 and (ii) a second externally accessible electrical contact(or electrode) 62, which are both arranged along a lower surface 54 ofthe flip chip LED 10 separated by a gap 59. In certain implementations,the passivation layer 50 comprises silicon nitride. The passivationlayer 50 includes a metal-containing interlayer 55 arranged therein,wherein the interlayer 55 may include (or consist essentially of) Al oranother suitable metal.

The LED 10 includes first and second arrays of microcontacts 63, 64extending through the passivation layer 50, with the first array ofmicrocontacts 63 providing conductive electrical communication betweenthe first electrical contact 61 and the first doped (e.g., n-doped)semiconductor layer 21, and with the second array of microcontacts 64providing conductive electrical communication between the secondelectrical contact 62 and the second (e.g., p-doped) semiconductor layer22. The first array of microcontacts 63 extends from the firstelectrical contact 61 (e.g., n-contact) through the passivation layer50, through openings defined in the interlayer 55, through openings 52defined in a first portion 48-1 of the barrier layer 48, throughopenings defined in a first portion 42-1 of the metal reflector layer42, through openings defined in a first portion 40-1 of the dielectricreflector layer 40, through the second semiconductor layer 22, andthrough the active region 25 to terminate in the first semiconductorlayer 21. Within openings defined in the interlayer 55, the firstportion 48-1 of the barrier layer 48, the first portion 42-1 of themetal reflector layer 42, and the first portion 40-1 of the dielectricreflector layer 40, dielectric material of the dielectric reflectorlayer 40 laterally encapsulates the microcontacts 63 to preventelectrical contact between the microcontacts 63 and the respectivelayers 55, 48, 42, 40. A set of vias 41-1 defined in the first portion40-1 of the dielectric reflector layer 40 contacts the first portion40-1 of the dielectric reflector layer 40 and the second semiconductorlayer 22, which may be beneficial to promote current spreading in theactive region 25. A second array of microcontacts 64 extends from thesecond electrical contact 62 through the passivation layer 50 andthrough openings defined in the interlayer 55 to at least one of (i) asecond portion 48-2 of the barrier layer 48, and (ii) a second portion42-2 of the metal reflector layer 42, wherein electrical communicationis established between the metal reflector layer 42 and the secondsemiconductor layer 22 through a set of vias 41-2 defined in a secondportion 40-2 of the dielectric reflector layer 40. Although the secondarray of microcontacts 64 is preferred in certain implementations, inother implementations, a single second microcontact may be substitutedfor the second array of microcontacts 64. Similarly, although it ispreferred in certain implementations to define multiple vias 41-2 in asecond portion 40-2 of the dielectric reflector layer 40, in otherimplementations, a single via or other single conductive path may besubstituted for the multiple vias 41-2.

Following formation of the passivation layer 50, one or more sideportions 16 extending between the outer major surface 11 of thesubstrate 15 and surface extensions 21A of the first semiconductor layer21 are not covered with passivation material. Such side portions 16embody a non-passivated side surface.

In operation of the flip chip LED 10, current may flow from the firstelectrical contact (e.g., n-contact or cathode) 61, the first array ofmicrocontacts 63, and the first (n-doped) semiconductor layer 21 intothe active region 25 to generate light emissions. From the active region25, current flows through the second (p-doped) semiconductor layer 22,vias 41-2, metal reflector layer portions 42-2, barrier layer portion48-2, and the second array of microcontacts 64 to reach the secondelectrical contact (e.g., p-contact or anode) 62. Emissions generated bythe active region 25 are initially propagated in all directions, withthe reflector layers 40, 42 serving to reflect emissions in a directiongenerally toward the substrate 15. As emissions reach the patternedsurface 14 arranged between the substrate 15 and the first semiconductorlayer 21, recessed/raised features 17 arranged in or on the patternedsurface 14 promote refraction rather than reflection at the patternedsurface 14, thereby increasing the opportunity for photons to pass fromthe first semiconductor layer 21 into the substrate 15 and thereafterexit the LED 10 through the outer major surface 11 and non-passivatedside portions 16. In certain implementations, one or more surfaces ofthe LED 10 may be covered with one or more lumiphoric materials (notshown), to cause at least a portion of emissions emanating from the LED10 to be up-converted or down-converted in wavelength.

FIGS. 2A and 2B are plan view photographs of a single flip chip LED 10similar in structure and operation to the flip chip LED 10 of FIG. 1.Referring to FIG. 2A, the flip chip LED 10 includes an outer majorsurface 11 arranged for extraction of LED emissions, and includes anactive region having a length L and a width W. In certain embodiments,the active region includes a length L of about 280 microns, and a widthW of about 220 microns, and a substrate 15 extends beyond the activeregion. Referring to FIG. 2B, the flip chip LED 10 includes a cathode 61and an anode 62 arranged along a lower surface 54. In certainembodiments, the cathode 61 includes length and width dimensions ofabout 95 microns by 140 microns, and the anode 62 includes length andwidth dimensions of about 70 microns by 170 microns.

FIGS. 3A and 3B are plan view photographs of a multi-LED chip includingan array of four flip chip LEDs 10 on a single transparent substrate 15,with each flip chip LED 10 being substantially similar in structure andoperation to the flip chip LED 10 of FIG. 1. The active area of eachflip chip LED 10 is spaced apart from the active area of each of otheradjacent flip chip LED 10 by a gap (e.g., 40 microns in a lengthdirection and 30 microns in a width direction). A central portion ofeach gap embodies a street 70 (e.g., having a width of about 10 microns)consisting solely of the substrate 15, whereas peripheral portions ofeach gap (between each street 70 and active areas of LEDs 10) includesthe substrate 15 as well as passivation material (e.g., passivationlayer 50 shown in FIG. 1). Each street 70 thus represents a boundarybetween adjacent flip chip LEDs 10. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged along a lower surface 54, and eachflip chip LED 10 is arranged to emit light through an outer majorsurface 11 of the substrate 15. The exposed cathodes 61 and anodes 62permit separate electrical connections to be made to each flip chip LED10, such that each flip chip LED 10 may be individually addressable andindependently controlled. If it were desired to separate the flip chipLEDs 10 from one another, then a conventional method to do so would beto utilize a mechanical saw to cut through the streets 70 to yieldindividual flip chip LEDs 10.

FIGS. 4A and 4B are plan view photographs of a multi-LED chip includingan array of one hundred flip chip LEDs 10 on a single transparentsubstrate 15, with each flip chip LED 10 being substantially similar instructure and operation to the flip chip LED 10 illustrated in FIG. 1.The flip chip LEDs 10 are separated from one another by gaps includingstreets 70. Each flip chip LED 10 includes an outer major surface 11arranged for extraction of LED emissions, and includes a cathode 61 andan anode 62 arranged along a lower surface 54. The exposed cathodes 61and anodes 62 permit separate electrical connections to be made to eachflip chip LED 10, such that each flip chip LED 10 may be individuallyaddressable and independently controlled.

As noted previously, the omnidirectional character of LED and phosphoremissions may render it difficult to prevent emissions of one LED (e.g.,a first pixel) from significantly overlapping emissions of another LED(e.g., a second pixel) of an array of flip chip LEDs arranged on asingle light-transmissive substrate. A single transparent substratesupporting multiple flip chip LEDs would permit light beams to travel innumerous directions, leading to light scattering and loss of pixel-likeresolution of emissions transmitted through the substrate. Problems oflight scattering and loss of pixel-like resolution would be furtherexacerbated by presence of one or more lumiphoric materials overlyingthe light extraction surface of a substrate, owing to theomnidirectional character of lumiphor emissions. Various embodimentsdisclosed herein address this issue by providing light segregationelements configured to reduce interaction between emissions of differentLEDs and/or lumiphoric material regions, thereby reducing scatteringand/or optical crosstalk and preserving pixel-like resolution of theresulting emissions. In certain embodiments, light segregation elementsmay extend from a light injection surface into a substrate, may extendfrom a light extraction surface into a substrate, may extend outwardfrom a light extraction surface, or any combination of the foregoing. Incertain embodiments, multiple light segregation elements may be definedby different methods in the same substrate and/or light emitting device.In certain embodiments, light segregation elements of different sizesand/or shapes may be provided in the same substrate and/or lightemitting device. For example, in certain embodiments, a first group oflight segregation elements having a first size, shape, and/orfabrication technique may extend from a light injection surface into aninterior of a substrate, and a second group of light segregationelements having a second size, shape, and/or fabrication technique mayextend from a light injection surface into an interior of a substrate,wherein the second size, shape, and/or fabrication technique differsfrom the first size, shape, and/or fabrication technique. In certainembodiments, light segregation elements may include walls that aresubstantially perpendicular to a primary light emitting surface of a LEDarray, or walls that are angled in a non-perpendicular fashion relativeto a primary light emitting surface of a LED array to reflect light in adesired manner (such as to collimate the emissions of each pixel of anarray). In certain embodiments, different forms of light segregation,light redirection, and/or light collimation elements may be located onor integral with different layers of a light emitting device including aLED array.

In certain embodiments, each flip chip LED of an array of LEDs supportedby a single substrate (e.g., a multi-LED chip) includes a greatestlateral dimension of no greater than about 400 microns, about 300microns, or about 200 microns. In certain embodiments, each flip chipLED of an array of LEDs supported by a single substrate includesinter-chip spacing of no greater than about 60 microns, or about 50microns, or about 40 microns, or about 30 microns, or about 20 microns,or about 10 microns. Such dimensional ranges provide a desirably smallpixel pitch.

In certain embodiments, a multi-LED chip includes LEDs serving as pixelseach having a substantially square shape. In certain embodiments, amulti-LED chip includes LEDs serving as pixels each having a rectangular(but non-square) shape. In other embodiments, LEDs may be provided aspixels having hexagonal shapes, round shapes, or other shapes.

In certain embodiments, a multi-LED chip may include LEDs provided in atwo-dimensional array as pixels of about 70 μm long×70 μm wide, eachincluding an active region of about 50 μm long×50 μm wide, therebyproviding a ratio of emitting area to total area of 0.0025 mm²/0.0049mm²=0.51 (or 51%). In certain embodiments, an array of at least 100 LEDs(as shown in FIG. 4B) may be provided in an area of no greater than 32mm long×24 mm wide, with spacing between LEDs (pixel pitch) of nogreater than 40 μm in the length direction and no greater than 30 μm inthe width direction. In certain embodiments, each LED may include anemissive area of 280 μm long×210 μm wide (totaling an area of 0.0588mm²). Considering a total top area of 320 μm long×240 μm wide (totalingan area of 0.0768 mm²) for each LED, a ratio of emissive area to totalarea (i.e., including emissive area in combination with non-emissivearea) along a major (e.g., top) surface is 76.6%. In certainembodiments, a light emitting device as disclosed herein includes aratio of emissive area to non-emissive (or dark) area along a major(e.g., top) surface of at least about 30%, at least about 40%, at leastabout 50% (i.e., about 1:1 ratio of emitting area to non-emitting (dark)area), at least about 55%, at least about 60%, at least about 65%, atleast about 70%, at least about 75%, or at least about 80%. In certainembodiments, one or more of the foregoing values may optionallyconstitute a range bounded by an upper value of no greater than 70%,75%, 80%, 85%, or 90%. In certain embodiments, an array of at least 1000LEDs may be provided.

Although FIGS. 2A, 2B, 3A, 3B, 4A, and 4B show each LED as including twon-contact vias (embodying vertically offset circles registered with then-contact or cathode 61), in certain embodiments, n-contacts and anyassociated n-contact vias may be shifted laterally and provided in adark area outside the emitting area of each LED.

In certain embodiments, one or more light segregation elements arearranged at least partially within a substrate supporting an array offlip chip LEDs (e.g., embodied in a multi-LED chip). In certainembodiments, a substrate supporting an array of flip chip LEDs (e.g., amulti-LED chip) includes a light injection surface receiving emissionsfrom the flip chip LEDs, and includes a light extraction surface(generally opposing the light injection surface) through which LEDemissions are intended to exit the substrate (e.g., to impinge on one ormore lumiphoric materials and/or exit the lighting device). In certainembodiments, one or more light segregation elements may extend from alight extraction surface of a substrate into an interior of thesubstrate, and/or one or more light segregation elements may extend froma light injection surface of the substrate into an interior of thesubstrate. In preferred embodiments, light segregation elements do notextend through an entire thickness of an interior portion of asubstrate, so that weakening or fracture of the substrate may beavoided. In certain embodiments, a first group of light segregationelements extends from a light injection surface into an interior of thesubstrate, and a second group of light segregation elements extends froma light extraction surface into the interior of the substrate. To avoidloss of light through lateral edges of a substrate, such edges may beadditionally coated or overlaid with a light affecting material, such asa light-reflective or light-absorptive material. One example of alight-reflective material that may be used is titanium dioxide [TiO₂],optionally provided in a powdered form and contained in a binder such assilicone. One example of a light-absorptive material that may be used iscarbon black, optionally provided in a powdered form and contained in abinder such as silicone. Other light-reflective materials,light-absorptive materials, and/or binders may be used.

Preferably, light segregation elements arranged within a substrate atleast partially bound different light-transmissive regions of thesubstrate, and are configured to reduce passage of LED emissionsgenerated by different flip chip LEDs between differentlight-transmissive regions. When a light extraction surface of asubstrate is overlaid with at least one lumiphoric material, suchmaterial may include multiple light output areas substantiallyregistered with the multiple light-transmissive regions of thesubstrate. In preferred embodiments, light segregation elements aresubstantially registered with boundaries (e.g., streets) between atleast some flip chip LEDs of an array of flip chip LEDs supported by thesubstrate (e.g., embodied in a multi-LED chip).

Various methods may be used for forming light segregation elements atleast partially within a substrate. In certain embodiments, recesses orgrooves may be formed in one or more major surfaces (faces) of asubstrate by mechanical techniques such as mechanical sawing (e.g.,using a diamond saw blade), by chemical techniques such as etching(optionally preceded by photolithographic patterning), or thermaltechniques such as laser ablation. After such recesses or grooves areformed, one or more light-affecting (e.g., light-reflective orlight-absorbing) materials may be deposited therein by any suitabletechnique. In certain embodiments, recesses or grooves may have asubstantially uniform width. In other embodiments, recesses or groovesmay have a width that varies with depth (e.g., such as may be formed bysawing or etching); in such a case, recesses or grooves may have slopingsidewalls (i.e., sidewalls that are non-perpendicular to a primary lightemitting surface of one or more LEDs). In certain embodiments, recesses,grooves, or other features may be defined by etching or sawing, followedby deposition of one or more light reflective, light absorptive, orother material into the recesses, grooves or features. Such features mayform a grid to extend between different LEDs or pixels of a lightemitting device, such as a multi-LED chip. In certain embodiments,desired features may be formed in a first layer, and a correspondingstructure or different features may be defined in a second layer that isbonded with the first layer to define pixels (or pixel-definingstructures) having desired characteristics. In certain embodiments,multiple light segregation elements may be formed by differentfabrication techniques in the same substrate and/or light emittingdevice. In certain embodiments, light segregation elements of differentsizes and/or shapes may be provided in the same substrate and/or lightemitting device.

As an addition or an alternative to the presence of light segregationelements arranged at least partially within a substrate, in certainembodiments, one or more light segregation elements may be arranged onor over a light extraction surface of a substrate. Such lightsegregation elements may define at least partial lateral boundaries forone or more lumiphoric material regions and/or for one or moremicrolenses. In such a case, light segregation elements are preferablyformed prior to addition of one or more lumiphoric material regionsand/or microlenses to a lighting device, such as a multi-LED chip. Incertain embodiments, light segregation elements may be deposited onsurfaces of a substrate by techniques such as three dimensionalprinting, by addition of one or more layers followed by selectiveremoval of the added one or more layers (e.g., by photolithographicetching), or by adhesion or other bonding of prefabricated elements.Preferably, such light segregation elements are substantially registeredwith boundaries between at least some flip chip LEDs of an array of flipchip LEDs supported by the substrate (e.g., of a multi-LED chip). Incertain embodiments, light segregation elements may be arrangedpartially within a substrate, and partially outside of a substrate. Incertain embodiments, light segregation elements arranged within asubstrate may be discontinuous with light segregation elements arrangedoutside a substrate.

As an addition or an alternative to the presence of light segregationelements arranged at least partially within a substrate or arranged on asubstrate, in certain embodiments, one or more light segregationelements may be arranged on or over one or more lumiphoric materialssupported by substrate. In certain embodiments, light segregationelements may be deposited on surfaces of one or more lumiphoricmaterials by techniques such as three dimensional printing, or byadhesion or other bonding of prefabricated elements.

In certain embodiments, optical structures or features may be used toenhance contrast and light segregation between pixels (thereby improvepixellation) and/or enhance homogeneity of aggregate emission of a lightemitting surface including multiple pixels, may include one or more ofthe following: light extraction structures, light segregation elements,lenses, collimation structures (e.g., including lenses and/or reflectivesidewalls), light containment structures or partitions, and combinationsof higher and lower refractive index materials (optionally provided inadjacent layers). Depending on the embodiment, these optical structuresor features can be formed in, formed on, or manufactured in or on one ormore of: a growth substrate, epitaxial layers, a carrier substrate(e.g., opposite the growth substrate or on a same side of a LED array asgrowth substrate), or a lumiphoric material (e.g., a lumiphoric layer).

FIGS. 5A-5C illustrate a multi-LED chip including an array of sixteenflip chip LEDs 10 on a single transparent substrate 15 facing upward invarious states of fabrication. Cathodes 61 and anodes 62 are facingdownward. As shown in FIG. 5A, the substrate 15 is continuous incharacter without any surface features along an outer major (lightextraction) surface 11. FIG. 5B shows the substrate 15 followingformation of three lengthwise grooves or recesses 72 extending from thelight extraction surface 11 into an interior of the substrate 15. Suchgrooves or recesses may be formed by any suitable techniques describedherein, including mechanical sawing. FIG. 5C shows the substrate 15following formation of three width-wise grooves or recesses 72 extendingfrom the light extraction surface 11 into an interior of the substrate15.

In certain embodiments, light segregation elements may be defined in asubstrate prior to the growth of an array of LEDs. In other embodiments,light segregation elements may be defined in a substrate substantiallysimultaneously with formation of streets between LEDs. Preferably,individual LEDs of the array of LEDs are grown between different lightsegregation elements of a plurality of light segregation elements.

FIG. 5D is a plan view illustration of a transparent substrate 15 facingdownward following formation of light segregation elements 74 in thesubstrate 15, with each light segregation element 74 extending from alight injection (lower) surface 54 of the substrate 15 into an interiorof the substrate 15. FIG. 5E is a plan view illustration of a multi-LEDchip including an array of sixteen flip chip LEDs 10 formed on thesubstrate 15 of FIG. 5D between the light segregation elements 74. Eachflip chip LED 10 includes an outer major surface (not shown) arranged toemit light into the light injection surface 54 of the substrate 15, andincludes a cathode 61 and an anode 62 arranged along the light injectionsurface 54. Although FIG. 5D shows the light segregation elements 74 asbeing defined in the substrate 15 prior to growth of the LEDs 10, incertain embodiments the light segregation elements 74 may be grownsubstantially simultaneously with formation of streets (not shown butregistered with the light segregation elements 74) between the LEDs 10.

FIGS. 6A-6C are side cross-sectional view illustrations of the multi-LEDchip of FIGS. 5A-5C on a single transparent substrate 15 facing downwardin various states of fabrication. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged over a functional stack 60(including semiconductor layers and an active region) supported by thesubstrate 15. Flip chip LEDs 10 are separated by lateral gaps includingstreets 70. The substrate 15 includes a lower (light injection) surface54 proximate to the flip chip LEDs 10 and opposing the light extractionsurface 11. The substrate 15 also includes side edges 12. As shown inFIG. 6A, grooves or recesses 72 extend from the light extraction surface11 into an interior of the substrate 15, and may be formed by anysuitable technique (e.g., mechanical sawing). Following formation of thegrooves or recesses 72, such features are filled with a suitablelight-affecting (e.g., light-reflective or light-absorptive) material toyield light segregation elements 74 at least partially embedded withinthe substrate 15, as shown in FIG. 6B. Optionally, planarization and/orcleaning steps may be performed on the light extraction surface 11before and/or after formation of the light segregation elements 74.Additionally, side edges 12 of the substrate 15 may be coated oroverlaid with a light-reflective or light-absorptive material 75 toprevent lateral escape of LED emissions generated by the flip chip LEDs10. As shown in FIG. 6C, after formation of the light segregationelements 74, at least one lumiphoric material 85 (including an outersurface defining multiple light output areas 86) may be deposited orotherwise provided over the light extraction surface 11. Areas betweenthe light segregation elements 74 (or between the light segregationelements and the side edges 12) define light-transmissive regions 80 ofthe substrate 15 that are suitable for transmitting LED emissions. Incertain embodiments, the light output areas 86 of the at least onelumiphoric material 85 are substantially registered with thelight-transmissive regions 80 of the substrate 15. In operation, the atleast one lumiphoric material 85 receives LED emissions transmittedthrough the substrate 15 between the light segregation elements 74,converts a portion of the received LED emissions to a differentwavelength, and transmits a combination of LED emissions and lumiphoremissions through the light output areas 86.

In certain embodiments, light segregation elements may extend from alight injection surface into an interior of the substrate. Additionally,in certain embodiments, a light extraction surface of a substrate may bepatterned or textured to enhance light extraction.

FIG. 7A is a side cross-sectional view illustration of a light emittingdevice (e.g., a multi-LED chip) including an array of flip chip LEDs 10on a single transparent substrate 15. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged over a functional stack 60 supportedby the substrate 15, with adjacent flip chip LEDs 10 being separated bylateral gaps including streets 70. The substrate 15 includes side edges12 coated with a light-reflective or light-absorptive material 75, and alight injection surface 54 that is proximate to the flip chip LEDs 10and that opposes a light extraction surface 11. Following formation ofgrooves or recesses in the substrate 15 extending from the lightinjection surface 54 into the substrate interior, such grooves orrecesses may be filled with a suitable light-affecting (e.g.,light-reflective or light-absorptive) material to yield lightsegregation elements 76 at least partially embedded within the substrate15. Areas between the light segregation elements 76 definelight-transmissive regions 80 of the substrate 15 that are suitable fortransmitting LED emissions. At least one lumiphoric material 85 havingan outer surface defining multiple light output areas 86 is arrangedover the light extraction surface 11, with the light output areas 86being substantially registered with the light-transmissive regions 80.

In certain embodiments, light segregation elements may extend from alight extraction surface into an interior of the substrate.Additionally, in certain embodiments, a light extraction surface of asubstrate may be patterned or textured to enhance light extraction.

FIG. 7B is a side cross-sectional view illustration of a light emittingdevice (e.g., a multi-LED chip) including an array of flip chip LEDs 10on a single transparent substrate 15. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged over a functional stack 60 supportedby the substrate 15, with adjacent flip chip LEDs 10 being separated bylateral gaps including streets 70. The substrate 15 includes side edges12 coated with a light-reflective or light-absorptive light-affectingmaterial 75, and a light injection surface 54 that is proximate to theflip chip LEDs 10 and that opposes a patterned or textured lightextraction surface 11A. Following formation of grooves or recesses inthe substrate 15 extending from the patterned or texture lightextraction surface 11A into the interior of the substrate 15, suchgrooves or recesses may be filled with a suitable light-affecting (e.g.,light-reflective or light-absorptive) material to yield lightsegregation elements 74 at least partially embedded within the substrate15. Areas between the light segregation elements 74 definelight-transmissive regions 80 of the substrate 15 that are suitable fortransmitting LED emissions. At least one lumiphoric material 85 havingan outer surface defining multiple light output areas 86 is arrangedover the light extraction surface 11A, with the light output areas 86being substantially registered with the light-transmissive regions 80.

In certain embodiments, a first group of light segregation elements mayextend from a light injection surface of a substrate into an interior ofthe substrate, and a second group of light segregation elements mayextend from a light extraction surface of the substrate into an interiorof the substrate.

FIG. 7C is a side cross-sectional view illustration of a light emittingdevice (e.g., a multi-LED chip) including an array of flip chip LEDs 10on a single transparent substrate 15. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged over a functional stack 60 supportedby the substrate 15, with adjacent flip chip LEDs 10 being separated bylateral gaps including streets 70. The substrate 15 includes side edges12 coated with a light-reflective or light-absorptive material 75, and alight injection surface 54 that is proximate to the flip chip LEDs 10and that opposes a patterned or textured light extraction surface 11A. Afirst group of light segregation elements 76 extends from the lightinjection surface 54 into an interior of the substrate 15, and a secondgroup of light segregation elements 74 extends from the light extractionsurface 11A into an interior of the substrate 15. Areas between thelight segregation elements 74, 76 define light-transmissive regions 80of the substrate 15 that are suitable for transmitting LED emissions. Atleast one lumiphoric material 85 having an outer surface definingmultiple light output areas 86 is arranged over the light extractionsurface 11A, with the light output areas 86 being substantiallyregistered with the light-transmissive regions 80.

In certain embodiments, microlenses may be arranged over different lightoutput areas of at least one lumiphoric material. Additionally, incertain embodiments, light extraction recesses may be defined in a lightextraction surface of a substrate. In certain embodiments, one lens maybe provided per pixel. In certain embodiments, lenses can be formed foreach the pixels through molding, or through dispensing of lumiphoric orother material into containment structures. Viscosity of one or morematerials used to produce lenses may be adjusted, depending on a desiredlens profile (e.g., concave, convex or undulating meniscus) to achievethe desired homogeneity and contrast properties of a LED array. Ifmolding is used, light extraction features, light redirection features,or any desired light shaping profile can be provided. Certainembodiments provided concave lenses overlying individual pixels, whereeach lens flattens toward the edge of a pixel.

In certain embodiments, containment and/or reflective structures formangled sidewalls that get thinner towards the top of the cross-sectionof the pixel, thereby collimating the light of each pixel to reducecross-talk while improving homogeneity between pixels. These structuresmay be provided in single substrates or layers, or formed in multiplesubstrates and/or layers to include an overall cross-section asdescribed herein.

Any light segregation elements, sidewalls, containment features, and thelike disclosed herein, can be specularly and/or diffusively reflective,and may embody shapes such as linear, piecewise linear, curved,parabolic, tapered (e.g., thinner toward an external surface), or otherdesired shapes. Various light affecting, light processing, lightsegregation, and/or light steering structures can be micromachined,etched, formed into, or deposited onto one or more layers of a lightemitting device disclosed herein.

FIGS. 8A-8D are side cross-sectional view illustrations of a lightemitting device (e.g., a multi-LED chip) including an array of flip chipLEDs 10 on a single transparent substrate 15 in various states offabrication. Light segregation elements 76 extend from a light injectionsurface 54 into an interior of the substrate 15. Each flip chip LED 10includes a cathode 61 and an anode 62 arranged over a functional stack60 supported by the substrate 15, with adjacent flip chip LEDs 10 beingseparated by lateral gaps including streets 70. The substrate 15includes side edges 12 coated with a light-reflective orlight-absorptive material 75. As shown in FIG. 8A, photoresist 81 may bepatterned over portions of an outer surface 11′ of the substrate 15. Asshown in FIG. 8A, regions containing the photoresist 81 are generallyregistered with the light segregation elements 76 as well as withboundaries between flip chip LEDs 10. After photoresist patterning iscomplete, a suitable chemical etchant may be supplied to the substrate15 to define light extraction recesses 82 between the regions ofphotoresist 81, as shown in FIG. 8B. Thereafter, at least one lumiphoricmaterial 85 may be provided at least partially within the lightextraction recesses 82, as shown in FIG. 8C. The at least one lumiphoricmaterial 85 includes an outer surface defining multiple light outputareas 86 substantially registered with light-transmissive regions 80 ofthe substrate 15 arranged between the light segregation elements 76.Optionally, microlenses 90 may be formed over the light output areas 86defined by the at least one lumiphoric material 85 and registered withlight-transmissive regions 80, as shown in FIG. 8D. In certainembodiments, the microlenses may be formed by three-dimensional printingor by bonding of prefabricated elements. In certain embodiments,microlenses of different shapes and/or configurations may be providedover different light output areas to output light beams with one or moredifferent properties. In certain embodiments, microlenses of differentshapes and/or configurations may be arranged to output light beamscentered in different directions. Further details regardingthree-dimensional printing of light-affecting elements including lensesare disclosed in U.S. Pat. No. 9,099,575, which is hereby incorporatedby reference as if fully set forth herein.

In certain embodiments, one or more light segregation elements may bearranged on or over a light extraction surface of a substrate (e.g., asraised features), in addition to the presence of light segregationelements arranged at least partially within a substrate.

FIGS. 9A-9C are side cross-sectional view illustrations of a lightemitting device (e.g., a multi-LED chip) including an array of flip chipLEDs 10 on a single transparent substrate 15 in various states offabrication to include light segregation elements 84 incorporatingraised features arranged on or above the light extraction surface 11 ofthe substrate 15. Each flip chip LED 10 includes a cathode 61 and ananode 62 arranged over a functional stack 60 supported by the substrate15, with adjacent flip chip LEDs 10 being separated by lateral gapsincluding streets 70. The substrate 15 includes side edges 12 subject tobeing coated with a light-reflective or light-absorptive material 75. Afirst group of light segregation elements 76 extends from the lightinjection surface 54 into an interior of the substrate 15, and a secondgroup of light segregation elements 74 extends from the light extractionsurface 11 into an interior of the substrate 15. Yet another group oflight segregation elements 84, which incorporates raised featuresextending beyond the light extraction surface 11, may be provided asextensions of the second group of light segregation elements 74. Asshown in FIG. 9B, at least one lumiphoric material 85 may be provided inrecesses bounded in part by the light segregation elements 84incorporating raised features and bounded in part by the lightextraction surface 11. An outer surface of the at least one lumiphoricmaterial 85 defines multiple light output areas 86. Areas between lightsegregation elements 74, 76 within the substrate 15 definelight-transmissive regions 80 of the substrate 15 that are suitable fortransmitting LED emissions. Similarly, areas between light segregationelements 84 extending beyond the substrate 15 (and optionally alsoextending beyond the at least one lumiphoric material 85) may bearranged to laterally surround the multiple light output areas 86. Themultiple light output areas 86 are substantially registered withlight-transmissive regions 80 of the substrate 15 arranged between theinternal light segregation elements 74, 76. Optionally, microlenses 90may be formed over the light output areas 86 defined by the at least onelumiphoric material 85 and registered with light-transmissive regions80, as shown in FIG. 9C.

In certain embodiments, one or more light segregation elements may bearranged on or over one or more lumiphoric materials supported bysubstrate, optionally in conjunction with one or more light segregationelements arranged at least partially within a substrate.

FIGS. 10A-10C are side cross-sectional view illustrations of a lightemitting device (e.g., a multi-LED chip) including an array of flip chipLEDs 10 on a single transparent substrate 15 in various states offabrication to include light segregation elements 87 arranged on or overat least one lumiphoric material 85. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged over a functional stack 60 supportedby the substrate 15, with adjacent flip chip LEDs 10 being separated bylateral gaps including streets 70. The substrate 15 includes side edges12 covered with a light-reflective or light-absorptive material 75. Afirst group of light segregation elements 76 extends from the lightinjection surface 54 into an interior of the substrate 15, and a secondgroup of light segregation elements 74 extends from the light extractionsurface 11 into an interior of the substrate 15. As shown in FIG. 10A,at least one lumiphoric material 85 may be provided over the lightextraction surface 11 following formation of the light segregationelements 74, 76 in the substrate 15, with an outer surface of the atleast one lumiphoric material 85 defining multiple light output areas 86that are substantially registered with light-transmissive regions 80 ofthe substrate 15 arranged between the internal light segregationelements 74, 76. Thereafter, as shown in FIG. 10B, yet another group oflight segregation elements 87, which incorporate raised featuresextending beyond the light extraction surface 11, may be formed on orover the at least one lumiphoric material 85 and are preferablyregistered with the other light segregation elements 74, 76. These lightsegregation elements 87 may be formed by various techniques such asthree-dimensional printing or by bonding of prefabricated elements.Optionally, microlenses 90 may be formed over the light output areas 86defined by the at least one lumiphoric material 85, between the lightsegregation elements 87, and registered with the light-transmissiveregions 80, as shown in FIG. 10C.

In certain embodiments, a light emitting device (e.g., a multi-LED chip)including an array of flip chip LEDs may be arranged for direct couplingto an active interface element such as an application specificintegrated circuit (ASIC) chip having electrode bond pads generallycorresponding to electrodes (cathodes and anodes) of the array of flipchip LEDs. In such an arrangement, the ASIC preferably includesintegrated transistors configured to accommodate switching of currentsupplied to individual chips of the array of flip chip LEDs.

In certain embodiments, a light emitting device (e.g., a multi-LED chip)including an array of flip chip LEDs may be arranged for coupling withan alternative (e.g., passive) interface element such as a carrier orsubmount, with electrical connections between the light emitting deviceand the interface element. In certain embodiments, an interface elementmay include a first array of bond pads or electrical contacts positionedon a first surface and arranged to make contact with electrodes of anarray of flip chip LEDs (e.g., embodied in one or more multi-LED chips),and a second array of bond pads or electrical contacts positioned on asecond surface and arranged to make contact with electrodes of one ormore ASICs or other switching apparatuses configured to accommodateswitching of current supplied to individual chips of the array of flipchip LEDs. Optionally, conductive vias may be defined through theinterface element to provide conductive paths between the first array ofbond pads or electrical contacts and the second array of bond pads orelectrical contacts.

FIG. 11A is a side cross-sectional exploded view illustration of themulti-LED chip of FIG. 6C arranged proximate to an interface element 94(e.g., optionally embodied in an application specific integrated circuit(ASIC) or a carrier or submount) and intermediately arranged solderbumps 93. The light emitting device includes multiple flip chip LEDs 10on a single transparent substrate 15. Each flip chip LED 10 includes acathode 61 and an anode 62 arranged over a functional stack 60 supportedby the substrate 15. Other features of the lighting device are describedherein in connection with FIG. 6C. The interface element 94 includesmultiple electrode pairs 91, 92 registered with the cathode 61 and anode62 pairs of the flip chip LEDs 10. FIG. 11B is a side cross-sectionalview of the multi-LED chip and interface element 94 of FIG. 11Afollowing completion of a solder bump bonding process and addition of anunderfill material 99 between the multi-LED chip and the interfaceelement 94. The solder bump bonding process may include heating andcompression of the solder bumps 93 to create conductive electricalconnections between the respective electrode pairs 91, 92 of theinterface element 94 and the paired cathodes 61 and anodes 62 of thelight emitting device. An exemplary underfill material may include epoxyfilled with spherical silicon dioxide [SiO₂] to enable the coefficientof thermal expansion (CTE) to be adjusted. Other underfill materials maybe used, and preferably comprise dielectric materials to preventshorting of electrically conductive connections between an interfaceelement and a multi-LED chip.

In certain embodiments, a light emitting device (e.g., a multi-LED chip)including an array of flip chip LEDs may be arranged for coupling to apassive interface element that provides electrical connections to anoff-board controller. In certain embodiments, orthogonally arranged(e.g., vertical and horizontal) conductors form rows and columns in agrid pattern, whereby individual flip chip LEDs (or pixels) are definedby each intersection of a row and column. Multiplex sequencing may beused to permit individual control of each LED of the array whileemploying a smaller number of conductors than the number of LEDs in thearray, either by utilizing a common-row anode or common-row cathodematrix arrangement, and brightness control may be provided by pulsewidth modulation.

FIGS. 12A-12E illustrate a first scheme for passively interfacing withan array of flip chip LEDs. FIG. 12A is a plan view illustration of alight emitting device (e.g., a multi-LED chip) including an array ofsixteen flip chip LEDs 10 on a single transparent substrate 15 with alower surface 54 of the substrate 15 as well as cathodes 61 and anodes62 facing upward. FIG. 12B is a plan view illustration of a lower layerof an electrical interface for the light emitting device of FIG. 12A. Afirst interface carrier 101 includes multiple horizontal string seriesconnections 103 each including multiple electrically conductive vias 102for coupling with anodes 62 of the light emitting device of FIG. 12A,and further including openings 104 permitting passage of conductive vias106 defined in a second interface carrier 105 (shown in FIG. 12C)forming an upper layer of the electrical interface. As shown in FIG.12C, multiple vertical string series connections 107 each includemultiple electrically conductive vias 106 arranged for coupling withcathodes 61 of the light emitting device of FIG. 12A. FIG. 12D is a planview illustration of the upper layer of FIG. 12C superimposed over thelower layer of FIG. 12B to form an electrical interface for the lightemitting device of FIG. 12A. FIG. 12E is a plan view illustration of theelectrical interface of FIG. 12D coupled with the light emitting deviceof FIG. 12A, whereby the horizontal string series connections 103 andthe vertical string series connections 107 permit each flip chip LED 10of the array to be individually controlled (e.g., utilizing multiplexsequencing).

FIGS. 13A-13E illustrate a second scheme for passively interfacing withan array of flip chip LEDs, including individual control of signalssupplied to cathodes of the array. FIG. 13A is a plan view illustrationof a light emitting device (e.g., a multi-LED chip) including an arrayof sixteen flip chip LEDs 10 on a single transparent substrate 15 with alower surface 54 of the substrate 15 as well as cathodes 61 and anodes62 facing upward. FIG. 13B is a plan view illustration of a lower layerof an electrical interface for the light emitting device of FIG. 13A. Afirst interface carrier 101 includes multiple horizontal string seriesconnections 103 each including multiple electrically conductive vias 102for coupling with anodes 62 of the light emitting device of FIG. 13A,and further including openings 104 permitting passage of conductive vias106 defined in a second interface carrier 105A (shown in FIG. 13C)forming an upper layer of the electrical interface. FIG. 13C is a planview illustration of the upper layer of an electrical interface for thelight emitting device of FIG. 13A, with multiple vertically arrangedparallel connections 107A each including multiple electricallyconductive vias 106 for coupling with cathodes 61 of the array. FIG. 13Dis a plan view illustration of the upper layer of FIG. 13C superimposedover the lower layer of FIG. 13B to form an electrical interface for thelight emitting device of FIG. 13A. FIG. 13E is a plan view illustrationof the electrical interface of FIG. 13D coupled with the light emittingdevice of FIG. 13A, whereby the horizontal string series connections 103and the vertically arranged parallel connections 107A permit each flipchip LED 10 of the array to be individually controlled.

As noted previously, solid state emitter arrays disclosed herein mayinclude various combinations of solid state light emitters (e.g., LEDs)and/or lumiphors configured to emit light of different wavelengths, suchthat an emitter array may be arranged to emit light of multiple dominantwavelengths. Various color combinations are contemplated for use indifferent applications.

FIGS. 14A-14D are plan view diagrams of addressable light emittingdevices (e.g., multi-LED chips) each including multiple light emitters110 (each including at least one solid state light emitter, optionallyin combination with at least one lumiphoric material) supported by asingle substrate 15 and configured to produce a different combination ofcolors. Such devices may each include an array of flip chip LEDs on asingle transparent substrate according to various embodiments disclosedherein. It is to be appreciated that particular color combinations andthe number of light emitters disclosed herein are provided by way ofexample only, and are not intended to limit the scope of the invention,since any suitable combination of colors and number of light emittersare contemplated.

FIG. 14A illustrates a light emitting device (e.g., a multi-LED chip)including four groups of four red (R), green (G), blue (B), and white(W) light emitters, with each light emitter arranged in a different rowamong rows 1 to 4 and a different column among columns A to D. A singlerepeat unit 112 including R-G-B-W light emitters is shown at upper left.In certain embodiments, the blue (B) emitters include LEDs lacking anylumiphoric material; the white (W) emitters include blue LEDs arrangedto stimulate emissions of a yellow and red lumiphor combination; thegreen (G) emitters include either green LEDs or blue LEDs arranged tostimulate green lumiphors; and the red (R) emitters include red LEDs orblue LEDs arranged to stimulate red lumiphors. In certain embodiments,the light emitting device of FIG. 14A may be useable as a sequentiallyilluminated LED display for producing color images or text and the like.

FIG. 14B illustrates a light emitting device (e.g., a multi-LED chip)including four groups of four short wavelength red (R₁), green (G), blue(B), and long wavelength red (R₂) light emitters, with each lightemitter arranged in a different row among rows 1 to 4 and a differentcolumn among columns A to D. A single repeat unit 112 includingR₁-G-B-R₂ light emitters is shown at upper left. In certain embodiments,the blue (B) emitters include LEDs lacking any lumiphoric material; theshort wavelength red (R₁) and long wavelength red (R₂) emitters eachinclude a red LED or a blue LED arranged to stimulate emissions of redlumiphors; and the green (G) emitters include either green LEDs or blueLEDs arranged to stimulate green lumiphors. Generally, solid-state lightsources (e.g., LEDs) having different dominant wavelengths in the redrange decline in luminous efficacy with increasing dominant wavelength,such that significantly more current may be required to generate thesame number of red lumens from a red LED having a long dominantwavelength in the red range than from a red LED having a shorterdominant wavelength; however, long dominant wavelength red emitters arewell-suited for producing high vividness illumination. In certainembodiments, the light emitting device of FIG. 14A may be useable as asequentially illuminated LED display or advertising billboard suitablefor producing very high vividness images, owing to the presence of longwavelength red emitters.

FIG. 14C illustrates a light emitting device (e.g., a multi-LED chip)including four groups of four blue shifted yellow (BSY), white (W),white (W), and amber (A) light emitters, with each light emitterarranged in a different row among rows 1 to 4 and a different columnamong columns A to D. A single repeat unit 112 including BSY-W-W-A lightemitters is shown at upper left. In certain embodiments, the blueshifted yellow (BSY) emitters include blue LEDs arranged to stimulateemissions of yellow phosphors providing better efficiency but poorercolor rendering than white LEDs; the white (W) emitters include blueLEDs arranged to stimulate emissions of a yellow and red lumiphorcombination; and the amber (A) emitters include either amber LEDs orblue LEDs arranged to stimulate amber lumiphors. In certain embodiments,the light emitting device of FIG. 14C may be useable in a vehicularheadlamp assembly, wherein the blue shifted yellow (BSY) emitters mayprovide high luminous efficacy with low to moderate color rendering whendesirable, the white (W) emitters may provide moderate luminous efficacywith high color rendering when desirable, and the amber (A) emitters mayprovide integrated turn signal utility.

FIG. 14D illustrates a light emitting device (e.g., a multi-LED chip)including four groups of four blue shifted yellow (BSY), amber (A), red(R), and blue shifted yellow (BSY) light emitters, with each lightemitter arranged in a different row among rows 1 to 4 and a differentcolumn among columns A to D. A single repeat unit 112 includingBSY-A-R-BSY light emitters is shown at upper left. In certainembodiments, blue shifted yellow (BSY) emitters include blue LEDsarranged to stimulate emissions of yellow phosphors providing betterefficiency but poorer color rendering than white LEDs; the amber (A)emitters include either amber LEDs or blue LEDs arranged to stimulateamber lumiphors; and the red (R) emitters include red LEDs or blue LEDsarranged to stimulate red lumiphors. In certain embodiments, the lightemitting device of FIG. 14D may be useable in a vehicular headlampassembly, wherein the blue shifted yellow (BSY) emitters may providehigh luminous efficacy with low to moderate color rendering,supplementation of BSY emissions with red (R) emissions may provideenhanced color rendering when desirable, and the amber (A) emitters mayprovide integrated turn signal utility.

In certain embodiments, a light emitting device may include or beassociated with driver circuitry and/or one or more sensors.

FIG. 15 is a simplified schematic diagram showing interconnectionsbetween components of a light emitting device including two emitterarrays (e.g., optionally embodied in two multi-LED chips) each includingindividually addressable flip chip LEDs, together with driver circuitryand one or more sensors. Although single lines are shown as couplingvarious components for simplicity, it is to be appreciated that eachline with a slash represents multiple conductors. The lighting deviceincludes first and second emitter arrays 120A, 120B and driver circuitry126 coupled to the emitter arrays 120A, 120B. Each emitter array 120A,120B includes multiple solid state light emitters (e.g., flip chip LEDssupported by a single substrate) that are separately coupled between thedriver circuitry 126 and ground, thereby permitting each constituentsolid state light emitter of each emitter array 120A, 120B to beindividually addressable and separately controlled. Each solid statelight emitter is configured to generate emissions (e.g., blue light,green light, UV emissions, or any other suitable wavelength range) inresponse to application of electric current, which is provided by thedriver circuitry 126. Emissions of each solid state light emitter may beproportional to the current provided thereto by the driver circuitry126. In each emitter array 120A, 120B, at least some solid stateemitters (or all solid state emitters) are overlaid with at least onelumiphoric material arranged to output any suitable wavelengths in thevisible range, such that aggregate emissions of each emitter array 120A,120B may include at least a portion of solid state emitter emissions incombination with lumiphor emissions. The resulting aggregate lightoutput from each emitter array 120A, 120B may include any desired coloror combination of colors.

In certain embodiments, each emitter array 120A, 120B includes differentindividual emitters that are configured to emit light of differentwavelengths, such that each emitter array 120A, 120B may be arranged toemit light of multiple dominant wavelengths. For example, in certainembodiments each emitter array 120A, 120B may be arranged to emit anytwo or more of short wavelength blue light, long wavelength blue light,cyan light, green light, yellow light, amber light, orange light, redlight, white light, blue shifted yellow light, and blue shifted greenlight. Solid state emitters of different dominant wavelengths and/orlumiphoric materials of different dominant wavelengths may be providedwithin one or more emitter arrays 120A, 120B to enable production oflight of different wavelengths. In certain embodiments, multiplelumiphor portions may be spatially separated from one another andarranged to receive emissions from respective solid state light sources.

The driver circuitry 126 includes power converter circuitry 124 andcontrol circuitry 122. The power converter circuitry 124 may beconfigured to receive power from a power source 132, which may be adirect current (DC) or alternating current (AC) power source, andprovides a desired current to each one of the solid state emitters inthe emitter arrays 120A, 120B. The control circuitry 122 may provide oneor more control signals to the power converter circuitry 124 in order tocontrol the amount of current provided to each one of the emitters inthe emitter arrays 120A, 120B such that individual emitters (e.g.,forming pixels) of each emitter array 120A, 120B are independentlyoperated. Each emitter array 120A, 120B has associated therewith aswitching circuitry group 128A, 128B including switching circuitrycoupled between each individual solid state emitter and ground. Incertain embodiments, the switching circuitry groups 128A, 128B mayinclude multiple metal-oxide-semiconductor field-effect transistors(MOSFETs) each including a drain contact coupled to the respectiveemitter, a source contact coupled to ground, and a gate contact coupledto the control circuitry 122. In such an instance, the control circuitry122 may be configured to vary a voltage provided to the gate contact ofeach transistor such that a current through each one of the solid stateemitters of the emitter arrays 120A, 120B is independently controllable.

In certain embodiments, the control circuitry 122 provides controlsignals based on input from at least one sensor 130. The at least onesensor 130 may embody any suitable sensor type, such as a photosensor, aradar sensor, an image sensor, a temperature sensor, a motion sensor, orthe like. In another embodiment, the control circuitry 122 may providecontrol signals based on a user input provided to the control circuitry122.

In certain embodiments, each emitter array 120A, 120B includes multiplesolid state emitters arranged to output light beams centered indifferent directions. Such functionality may be provided, for example,with microlenses of different shapes and/or configurations. In certainembodiments, different microlenses may be arranged over different lightoutput areas of at least one lumiphoric material arranged over asubstrate supporting multiple flip chip LEDs. The ability to outputlight beams centered in different directions may be beneficial in thecontext of vehicular (e.g., automotive) headlamps, in which it may bedesirable to selectively illuminate and darken different zones forwardof a moving vehicle to provide maximum illumination without dazzling orimpairing the vision of drivers of oncoming or adjacent vehicles. Forexample, multiple sensors 130 of any suitable types (e.g., radarsensors, photosensors, image sensors, thermal sensors, or the like) maybe used to discriminate between different illumination targets such asother vehicles, pedestrians, animals, and other objects, and toselectively illuminate or avoid illumination of selected illuminationtargets depending on the character of the illumination target,environmental conditions, road conditions, or the like.

In certain embodiments, at least one array of LEDs supported by a lighttransmissive or transparent substrate (optionally embodying a substrateon which the LEDs were grown) arranged to transmit emissions of the atleast one array may be further supported by a light transmissive ortransparent carrier that is further arranged to transmit emissionsgenerated by the array. In certain embodiments, multiple arrays of LEDs(e.g., multiple multi-LED chips each including a substrate) are mountedto a single carrier, in order to form a modular multi-array lightemitting device. In certain embodiments, the carrier may includeinternal and/or external light segregation elements, preferablyregistered with light segregation elements of the substrate, such thatlight extraction or light output areas of the carrier are registeredwith light-transmissive regions of the one or more substrates supportedby the carrier. In certain embodiments, a light extraction surface of acarrier may include one or more textured or patterned regionscorresponding to light output areas. In certain embodiments, a lightextraction surface of a carrier may be overlaid with at least onelumiphoric material (e.g., such as one or more lumiphoric materialsarranged in a uniform manner over the entire light extraction surface,or different lumiphoric materials arranged over different regions of thelight extraction surface). In certain embodiments, at least onelumiphoric material may be arranged between at least one substrate andthe carrier.

FIG. 16 is a side cross-sectional view illustration of a light emittingdevice including an array of flip chip LEDs 10 on a transparentsubstrate 15 that is further supported by a light-transmissive (ortransparent) carrier 135. Each flip chip LED 10 includes a cathode 61and an anode 62 arranged over a functional stack 60 supported by thesubstrate 15, with adjacent flip chip LEDs 10 being separated by lateralgaps including streets 70. The substrate 15 includes side edges 12coated with a light-reflective or light-absorptive material 75, and alight injection surface 54 that is proximate to the flip chip LEDs 10and that opposes a light extraction surface 11. A first group of lightsegregation elements 76 extends from the light injection surface 54 intoan interior of the substrate 15. Notably, the light segregation elements76 include a non-uniform width (such as may be formed by sawing oretching), wherein the width narrows with depth of extension into theinterior of the substrate 15. The carrier 135 is bonded (e.g., viadirect bonding) or otherwise affixed to the substrate 15, wherein alight injection surface 134 of the carrier 135 is adjacent to the lightextraction surface 11 of the substrate 15. The carrier 135 includesinternal light segregation elements 136 extending from a patterned ortextured light extraction surface 138 into an interior of the carrier135, wherein the light segregation elements 136 include a width thatnarrows with depth of extension into the interior of the carrier 135. Atleast one lumiphoric material 85 is arranged on or over the lightextraction surface 138 of the carrier 135, with the at least onelumiphoric material 85 including an outer surface defining multiplelight output areas 86. Additional light segregation elements 139 areoptionally arranged over an outer surface of the least one lumiphoricmaterial 85, with each additional light segregation element 139optionally including a width that tapers with distance away from the atleast one lumiphoric material 85. Areas between the light segregationelements 76 (or between the light segregation elements 76 and the sideedges 12) of the substrate 15, and between the light segregationelements 136 of the carrier 135, define light-transmissive regions 80 ofthe substrate 15 and the carrier 135 that are suitable for transmittingLED emissions. Preferably, the light output areas 86 of the at least onelumiphoric material 85 are substantially registered with thelight-transmissive regions 80 of the substrate 15 and the carrier 135.In operation, the at least one lumiphoric material 85 receives LEDemissions transmitted through the substrate 15 between the lightsegregation elements 76 and transmitted through the carrier 135 betweenthe light segregation elements 136, converts a portion of the receivedLED emissions to a different wavelength, and transmits a combination ofLED emissions and lumiphor emissions through the light output areas 86.Although only a single substrate 15 supporting a single array of LEDs 10is shown in FIG. 16, it is to be appreciated that in certainembodiments, a multiplicity of substrates, each including an array ofLEDs, may be supported by a single carrier and thereby form a largearray including multiple sub-arrays.

FIG. 17 is a side cross-sectional view illustration of a light emittingdevice including a first array of flip chip LEDs 10A on a firsttransparent substrate 15A (e.g., embodied in a first multi-LED chip) anda second array of flip chip LEDs 10B on a second transparent substrate15B (e.g., embodied in a second multi-LED chip), wherein both substrates15A, 15B are joined (e.g., bonded) to a carrier 135. As illustrated inFIG. 17, each array of flip chip LEDs 10A, 10B is substantiallyidentical. Within each array, each flip chip LED 10A, 10B includes acathode 61A, 61B and an anode 62A, 62B arranged over a functional stack60A, 60B supported by the respective substrate 15A, 15B, with adjacentflip chip LEDs 10A, 10B being separated by lateral gaps includingstreets 70A, 70B. Each substrate 15A, 15B includes side edges 12A, 12Bcoated with a light-reflective or light-absorptive material 75A, 75B,and a light injection surface 54A, 54B that is proximate to the flipchip LEDs 10A, 10B and that opposes a light extraction surface 11A, 11B.Each substrate 15A, 15B includes a first group of light segregationelements 76A, 76B extending from the light injection surface 54A, 54Binto an interior of the substrate 15A, 15B, and includes a second groupof light segregation elements 74A, 74B extending from the lightextraction surface 11A, 11B into the interior of the substrate 15A, 15B.The carrier 135 is bonded (e.g., via direct bonding) or otherwiseaffixed to the substrates 15A, 15B, wherein a light injection surface134 of the carrier 135 is adjacent to the light extraction surfaces 11A,11B of the substrates 15A, 15B. The carrier 135 includes internal lightsegregation elements 136 extending from a patterned or textured lightextraction surface into an interior of the carrier 135. The lightextraction surface of the carrier 135 includes textured or patternedlight extraction regions 138 segregated by untextured (e.g., flat)regions 137. At least one lumiphoric material 85 is arranged on or overthe light extraction surface of the carrier 135, with the at least onelumiphoric material 85 including an outer surface defining multiplelight output areas 86.

Continuing to refer to FIG. 17, areas between the light segregationelements 76A, 76B, 74A, 74B (or between the light segregation elements76A, 76B, 74A, 74B and the side edges 12A, 12B) of the substrates 15A,15B, and between the light segregation elements 136 of the carrier 135,define light-transmissive regions 80A, 80B of the substrates 15A, 15Band the carrier 135 that are suitable for transmitting LED emissions.Preferably, the textured or patterned light extraction regions 138 ofthe carrier 135 and the light output areas 86 of the at least onelumiphoric material 85 are substantially registered with thelight-transmissive regions 80A, 80B of the substrates 15A, 15B and thecarrier 135.

In operation of the device of FIG. 17, the at least one lumiphoricmaterial 85 receives LED emissions transmitted through the substrates15A, 15B between the light segregation elements 76A, 76B, 74A, 74B andtransmitted through the carrier 135 between the light segregationelements 136, converts a portion of the received LED emissions to adifferent wavelength, and transmits a combination of LED emissions andlumiphor emissions through the light output areas 86. Preferably, eachLED 10A, 10B is independently controlled, and pixel-like resolution ofimages produced by arrays of the device is preserved in the resultingemissions.

FIG. 18 is a side cross-sectional view illustration of a light emittingdevice similar to the device of FIG. 17, but wherein at least onelumiphoric material is arranged in at least one layer between substrates15A, 15B and a carrier 135. Referring to FIG. 18, the light emittingdevice includes a first array of flip chip LEDs 10A on a firsttransparent substrate 15A (e.g., embodied in a first multi-LED chip) anda second array of flip chip LEDs 10B on a second transparent substrate15B (e.g., embodied in a second multi-LED chip), wherein both substrates15A, 15B are joined (e.g., bonded) to a carrier 135. Each array may besubstantially identical in character. Within each array, each flip chipLED 10A, 10B includes a cathode 61A, 61B and an anode 62A, 62B arrangedover a functional stack 60A, 60B supported by the respective substrate15A, 15B, with adjacent flip chip LEDs 10A, 10B being separated bylateral gaps including streets 70A, 70B. Each substrate 15A, 15Bincludes side edges 12A, 12B coated with a light-reflective orlight-absorptive material 75A, 75B, and a light injection surface 54A,54B that is proximate to the flip chip LEDs 10A, 10B and that opposes alight extraction surface 11A, 11B. Each substrate 15A, 15B includes afirst group of light segregation elements 76A, 76B extending from thelight injection surface 54A, 54B into an interior of the substrate 15A,15B, and includes a second group of light segregation elements 74A, 74Bextending from the light extraction surface 11A, 11B into the interiorof the substrate 15A, 15B. At least one lumiphoric material 85 includinga light extraction surface 86′ is arranged in at least one region orlayer between the substrates 15A, 15B and the carrier 135. In certainembodiments, the at least one lumiphoric material 85 may be arranged ina light-transmissive adhesive material, such as epoxy or silicone, thatprovides a bond between the substrates 15A, 15B and the carrier 135,with a light injection surface 134 of the carrier 135 being adjacent tothe at least one lumiphoric material 85.

Continuing to refer to FIG. 18, areas between the light segregationelements 76A, 76B, 74A, 74B (or between the light segregation elements76A, 76B, 74A, 74B and the side edges 12A, 12B) of the substrates 15A,15B define light-transmissive regions 80A, 80B that are suitable fortransmitting LED emissions to impinge on the at least one lumiphoricmaterial 85 having light output areas 86′. Additionally, areas betweenthe light segregation elements 136 of the carrier 135 define additionallight-transmissive regions 80A′, 80B′ that are suitable for transmittinga combination of lumiphor material emissions and unconverted LEDemissions, wherein the combined emissions exit the device through thetextured or patterned light extraction regions 138 of the lightextraction surface of the carrier 135. Preferably, the textured orpatterned light extraction regions 138 of the carrier 135 and the lightoutput areas 86′ of the at least one lumiphoric material 85 aresubstantially registered with the light-transmissive regions 80A, 80B ofthe substrates 15A, 15B and the additional light-transmissive regions80A′, 80B′ of the carrier 135. Additionally, in preferred embodiments,each LED 10A, 10B is independently controlled, and pixel-like resolutionof images produced by arrays of the device is preserved in the resultingemissions.

FIG. 19 is a top plan view of a light emitting device including fourindividually addressable arrays (or subarrays) of LEDs 10A-10D supportedby light-transmissive substrates 15A-15D arranged in close proximity toone another and further supported by a light-transmissive carrier 135.Each array (or subarray) may be monolithic in character, each includingmultiple LEDs 10A-10D grown on a single substrate 15A-15D to yield amulti-LED chip. As illustrated in FIG. 19, cathodes 61A-61D and anodes62A-62D of the LEDs 10A-10D are facing downward, and a light extractionsurface 138 of the carrier 135 is facing upward. Each substrate 15A-15Dmay abut another substrate 15A-15D or may be separated by a small gap150, preferably in such a manner as to maintain a constant pixel pitch(i.e., spacing between individual LEDs 10A-10D) that is substantiallyidentical between the arrays 10A-10D supported by the differentsubstrates 15A-15D. Restated, the spacing between subarrays (eachincluding a substrate 15A-15D supporting LEDs 10A-10D) may be closelymatched to the spacing between pixels within each subarray. Eachsubstrate 15A-15D (and optionally also the carrier 135) includes lightsegregation elements 74A-74D between individual LEDs 10A-10D.Preferably, at least one lumiphoric material (not shown) is arranged onor along the light extraction surface 138 of the carrier 135, or betweenthe carrier 135 and the substrates 15A-15D. Although only four subarraysof LEDs 10A-10D (each supported by a substrate 15A-15D) are shown inFIG. 19, it is to be appreciated that any suitable number of subarraysand substrates may be supported by a single carrier 135 to form a largecomposite array with any desired number of pixels (i.e., LEDs 10A-10D).Preferably, each LED 10A-10D is independently controlled, and pixel-likeresolution of images produced by the entire composite array of LEDs10A-10D is preserved in the resulting light emissions.

In certain embodiments, each subarray of LEDs is monolithic and/oridentical in character. The use of a carrier supporting multiple LEDsubarrays may avoid practical difficulties (e.g., from a yield and costperspective) in forming a single, large array of junctions on a singlelarge growth substrate.

In certain applications, an entire composite array and/or one or moresubarrays may have a tolerance of one, two, or another number ofinactive pixels for certain applications (e.g., automotive headlamps) inwhich resolution may be less critical than in sequentially illuminatedLED displays. In certain embodiments, different pixels may be arrangedto output light of different dominant wavelengths.

Various embodiments disclosed herein are directed to providing strongcontrast and/or sharpness between lit and unlit regions of LED arrayswhile seeking to reduce or eliminate crosstalk or light spill betweensuch regions. However, when adjacent LEDs are lit, the presence of lightsegregation elements between such LEDs (which are intended to reduce oreliminate crosstalk) may lead to non-illuminated or “dark” zones betweenthe LEDs, thereby degrading homogeneity of the composite emissions.Various embodiments described hereinafter are intended to provide strongcontrast and/or sharpness between lit and unlit regions of a LED array,while enhancing homogeneity of composite emissions when adjacent LEDs ofthe array are lit. For example, in certain embodiments, an array of LEDs(optionally embodied in a multi-LED chip) defines multiple pixels, andmultiple inter-pixel light spreading regions are configured to transmitlight through border portions of the pixels to enhance inter-pixelillumination at light-emitting surface portions that are registered withor proximate to a plurality of light segregation elements. In certainembodiments, multiple light redirecting regions are arranged at leastpartially within a light-transmissive secondary substrate overlying alumiphoric material that is arranged over a substrate that includes theplurality of light segregation elements, with the light redirectingregions being configured to enhance illumination of light emittingsurface portions of the solid state light emitting device that areoverlying and registered with the plurality of light segregationelements. The foregoing items (e.g., inter-pixel light spreading regionsand/or light redirecting regions) are preferably configured to reduceappearance of non-illuminated or “dark” regions (corresponding to lightsegregation elements) between the LEDs when they are illuminated. Incertain embodiments, light segregation elements may have a width in arange of about 10 μm to 30 μm, or in a range of about 15 μm to about 25μm.

Homogeneity and crosstalk issues associated with multi-LED arrays may bebetter understood with reference to FIGS. 20A-20C. FIG. 20A is a topplan view digital photograph of a light emitting device (e.g., amulti-LED chip) including an array 152 of sixteen LEDs (e.g., formingsixteen pixels) with light segregation elements 156 arranged betweenindividual LEDs (e.g., LED 155A1-155A4) forming a dark grid, and witheach LED shown in a non-illuminated state. The LEDs are arranged in fourcolumns (e.g., including columns 154A, 154B). The light segregationelements 156 are visible as a dark grid that separates lighter colored(e.g., gray) squares embodying light emitting surface portions or pixelsof the LED array 152. FIG. 20B is a top plan view digital photograph ofthe LED array 152 of the light emitting device of FIG. 20A with currentsupplied to the rightmost column 154A of four LEDs 155A1-155A4, whichare illuminated. As shown, the adjacent column 154B of LEDs (the secondcolumn from the right) is partially illuminated due to spillover oflight from the rightmost column 154A of LEDs, and non-illuminated (or“dark”) zones corresponding to light segregation elements 156 arevisible between adjacent illuminated LEDs. FIG. 20C is a color invertedversion of the digital photograph of FIG. 20B. To promote enhancedcontrast and/or sharpness between lit and unlit regions, it would bedesirable to eliminate or at least reduce crosstalk or light spilloverbetween the rightmost column 154A of LEDs 155A1-155A4 and the adjacentcolumn 154B of LEDs. To promote homogeneity of composite emissions ofthe LED array 152, it would be desirable to eliminate or at least reducethe appearance of the dark grid corresponding to light segregationelements 156 between individual LEDs (e.g., pixels), including but notlimited to LEDs 155A1-155A4.

FIG. 21A is a top view intensity mapped image of an eight-pixel portionof a light emitting device (e.g., a multi-LED chip) including an array162 of multiple LEDs forming pixels, showing a leftmost column 164A offour LEDs 165A1-165A4 being illuminated. As shown, an adjacent column164B of four LEDs is partially illuminated due to spillover of lightfrom the leftmost column 164A of LEDs, and non-illuminated or “dark”zones are visible between adjacent illuminated LEDs corresponding tolight segregation elements 166 provided between the LEDs (e.g., LEDs165A1-165A4). Vertical lines 167 spanning over each LED 165A1-165A4 ofthe leftmost column 164A of LEDs are shown. FIG. 21B includes fouroverlaid plots of relative light intensity (percent) versus position(millimeters) for the leftmost column of four illuminated LEDs of FIG.21A, with each plot corresponding to one of the four vertical lines 167extending through the leftmost column 164A of LEDs 165A1-165A4 in FIG.21A. As shown in FIG. 21B, relative light intensity drops precipitously(e.g., including reductions of about 70%) at locations between LEDs165A1-165A4 corresponding to the presence of light segregation elements166. As noted previously, to promote homogeneity of composite emissionsof the LED array, it would be desirable to eliminate or at least reducethe appearance of the dark grid corresponding to light segregationelements 166 between individual LEDs (e.g., pixels).

In certain embodiments, a solid state light emitting device may includean array of LEDs arranged to transmit LED emissions through multiplelight-transmissive portions of at least one substrate, multiple lightsegregation elements arranged at least partially within the at least onesubstrate, and multiple inter-pixel light spreading regions configuredto transmit light through border portions of pixels defined by thelight-transmissive portions of the at least one substrate to enhanceinter-pixel illumination at light-emitting surface portions that areregistered with or proximate to the light segregation elements. Incertain embodiments, the at least one substrate consists of a singlesubstrate supporting the array of LEDs (e.g., such as by growth ofmultiple LEDs on or over the substrate). In such an instance, adjacentLEDs may be separated by recesses or grooves formed in the substrate,and light segregation elements (optionally in combination with at leastone light-transmissive material) may be provided at least partiallywithin the recesses or grooves. In other embodiments, each LED includesa corresponding substrate portion, such that the at least one substrateembodies the multiple substrate portions, optionally mounted on a singlesubmount or other mounting surface, wherein light segregation elements(optionally in combination with at least one light-transmissivematerial) may be provided between and/or along lateral surfaces ofadjacent LEDs.

Certain embodiments of the present disclosure are directed to lightemitting devices including multiple light segregation elements arrangedentirely within at least one substrate (e.g., within recesses or groovesdefined in the at least one substrate between adjacent LEDs) of a solidstate light emitting device (e.g., a multi-LED chip), and multipleinter-pixel light spreading regions including at least onelight-transmissive material arranged at least partially within the atleast one substrate and over the light segregation elements. In certainembodiments, multiple recesses or grooves may be defined in at least onesubstrate, at least one material (e.g., preferably silver or whitelight-reflective material, or less preferably a light absorptivematerial such as carbon black) may be deposited in the recesses orgrooves to form light segregation elements, and the at least onelight-transmissive material may be deposited over the light segregationelements to form inter-pixel light spreading regions configured totransmit light through border portions of pixels defined bylight-transmissive portions of the at least one substrate. Thereafter,at least one lumiphoric material may be deposited or otherwise providedover the at least one substrate as well as over the at least onelight-transmissive material forming the inter-pixel light spreadingregions. In certain embodiments, the recesses or grooves alone (i.e.,without addition of light reflective or light absorptive material) maybe used to provide light segregation utility.

FIGS. 22A-22C illustrate a portion of a solid state light emittingdevice 168 (e.g., a multi-LED chip) including features as describedabove following performance of sequential fabrication steps. FIG. 22A isa side cross-sectional schematic view of the portion of solid statelight emitting device 168 during fabrication, including two LEDs 10A,10B following formation of a recess or groove 179 in at least a portionof a substrate (including substrate portions 173A, 173B). Each LED 10A,10B includes an anode-cathode pair 171A-172A, 171B-172B proximate to afunctional stack 170A, 170B that is arranged to emit light into thesubstrate portions 173A, 173B. In this regard, each LED 10A, 10B mayembody a flip chip LED. In certain embodiments, the functional stacks170A, 170B and/or substrate portions 173A, 173B of different LEDs 10A,10B may be integrally formed and/or connected via at least oneinterconnect 170′; alternatively, each LED 10A, 10B may be physicallyand/or electrically disconnected relative to one another. Each substrateportion 173A, 173B includes lateral surfaces 174A, 174B (includinglateral surfaces bounding the recess or groove 179) and includes aprimary light-emitting surface portion 175A, 175B.

FIG. 22B illustrates the portion of the solid state lighting emittingdevice 168 of FIG. 22A following sequential addition of a first material(e.g., a light reflective material) serving as a light segregationelement 176 and addition of a second material (e.g., alight-transmissive material, optionally including a light scatteringmaterial such as fused silica, fumed silica, or the like) serving as alight spreading and/or light redirecting element 177 in the recess orgroove 179 (shown in FIG. 22A) to form a filled recess 178. FIG. 22Cillustrates the portion of the solid state light emitting device 168 ofFIG. 22B following application of a lumiphoric material 180 over theprimary light-emitting surface portions 175A, 175B of the substrateportions 173A, 173B and the filled recess 178. In certain embodiments,the lumiphoric material 180 includes phosphor particles dispersed in anappropriate carrier (e.g., silicone or epoxy) that may be cured toadhere the lumiphoric material 180 to the substrate portions 173A, 173B.

In operation of the solid state light emitting device 168, current issupplied to the LEDs 10A, 10B via the anode-cathode pairs 171A-172A,171B-172B, and LED emissions are generated in the functional stacks170A, 170B. Such LED emissions are propagated through the substrateportions 173A, 173B, with a majority impinging on the layer oflumiphoric material 180 above the primary light-emitting surfaceportions 175A, 175B. Shallow angle LED emissions are blocked fromtransmission between substrate portions 173A, 173B by the lightsegregation element 176; however, a fraction of moderate angle emissionsmay transit through the light spreading and/or light redirecting element177 to impinge on a portion of the lumiphoric material 180 registeredwith the filled recess 178 (which is registered with the lightsegregation element 176). In this manner, a region forward of the lightsegregation element 176 is illuminated, appearance of a non-illuminatedor dark zone between the substrate portions 173A, 173B is reduced, andhomogeneity of light emissions of the light emitting device is enhanced.

FIGS. 23A and 23B illustrate a portion of a solid state light emittingdevice 182 (e.g., a multi-LED chip) similar to the solid state lightemitting device 168 of FIG. 22C, but with addition of an elevatedlight-transmissive material region 184 registered with the lightsegregation element 176. In certain embodiments, the elevatedlight-transmissive material region 184 includes a bead of material suchas silicone, optionally including one or more diffuser materials orother materials. As shown in FIG. 23A, the light emitting device 182includes two LEDs 10A, 10B separated by a recess or groove (i.e., a gap)filled with sequentially arranged materials forming a light segregationelement 176 and a light spreading and/or light redirecting element 177.The elevated light-transmissive material region 184 embodies an upwardextension of the light spreading and/or light redirecting element 177and includes a width 185 that permits the elevated light-transmissivematerial region 184 to overlap border portions of substrate portions173A, 173B, to further enhance illumination of the portion of the layerof lumiphoric material 180 that overlies the light segregation element176. Each LED 10A, 10B includes an anode-cathode pair 171A-172A,171B-172B proximate to a functional stack 170A, 170B that is arranged toemit light into a substrate portion 173A, 173B. In certain embodiments,the functional stacks 170A, 170B and/or substrate portion 173A, 173B ofdifferent LEDs 10A, 10B may be integrally formed and/or connected via atleast one interconnect 170′; alternatively, each LED 10A, 10B may bephysically and/or electrically disconnected relative to one another.Each substrate portion 173A, 173B includes lateral surfaces 174A, 174B(including lateral surfaces bounding the recess or groove) and includesa primary light-emitting surface portion 175A, 175B. A layer oflumiphoric material 180 is provided over the substrate portions 173A,173B as well as the elevated light-transmissive material region 184,with the lumiphoric material 180 including a transition 181 from aconstant height to an increased height to accommodate the elevatedheight of the elevated light-transmissive material region 184. FIG. 23Bis a top plan view of at least a portion of the solid state lightemitting device portion of FIG. 23A including four LEDs, with dashedlines depicting the elevated light-transmissive material region.Operation of the solid state light emitting device 182 is substantiallysimilar to operation of the solid state light emitting device 168 ofFIG. 22C. In alternative embodiments, the elevated light-transmissivematerial region 184 may be arranged above the layer of lumiphoricmaterial 180.

In certain embodiments, a substrate portion of a solid state lightemitting device (e.g., a LED chip) supporting multiple LEDs may beprovided with excess thickness to avoid bowing or warping, and thesubstrate portion may be thinned or removed (e.g., by chemicalmechanical planarization, mechanical polishing, chemical etching, and/oranother suitable polishing technique) after it is mounted to a carriersubstrate or submount. For example, a substrate portion may initiallyhave a thickness in a range of 300 μm to 500 μm, but after mounting andpolishing, the substrate portion may have a final thickness in a rangeof about 50 μm to 100 μm. A preferred carrier substrate or submount forsuch an application includes a semiconductor (e.g., silicon) wafer withelectrically conductive traces (e.g., arranged in, on, or overdielectric layers overlying the substrate to facilitate formation ofcomplex, non-intersecting trace patterns), whereby the semiconductorwafer may provide significantly enhanced flatness relative toconventional circuit board materials (e.g., resin, FR4, or the like).Preferably, a carrier substrate or submount includes multiple electrodepairs, and the mounting establishes electrically conductive paths (e.g.,using solder paste, solder bumps, or the like) between the anode-cathodepairs of LEDs and electrode pairs of the carrier substrate or submount.Mounting a substrate portion having excess thickness and supportingmultiple LEDs over a semiconductor material-based carrier substrate orsubmount promotes enhanced flatness of mating surfaces to enableformation of reliable electrical connection. After mounting is complete,the substrate portion(s) may be thinned to enhance light extraction. Inthis context, the submount is used to support the LED chip to permitprocessing of the LED chip (e.g., with possible processing stepsincluding, but not limited to, thinning or removal of the growthsubstrate), such that the submount acts as a carrier substrate.

FIGS. 24A and 24B illustrate a portion of a solid state light emittingdevice (e.g., a multi-LED chip) 186 in different states of fabrication,with the respective figures showing substrate portions with excessthickness (in FIG. 24A) and after mounting, substrate thinning, andlumiphoric material deposition (in FIG. 24B). As shown in FIG. 24A, thesolid state light emitting device 186 includes two LEDs 10A, 10Bseparated by a gap (e.g., recess or groove) filled with sequentiallyarranged materials forming a light segregation element 176 and a lightspreading and/or light redirecting element 177. Each LED 10A, 10Bincludes an anode-cathode pair 171A-172A, 171B-172B proximate to afunctional stack 170A, 170B that is arranged to emit light into asubstrate portion 173A, 173B that includes lateral surfaces 174A, 174B(i.e., including lateral surfaces bounding the filled gap). In certainembodiments, the functional stacks 170A, 170B and/or substrate portions173A, 173B of different LEDs 10A, 10B may be integrally formed and/orconnected via at least one interconnect 170′; alternatively, each LED10A, 10B may be physically and/or electrically disconnected relative toone another. With continued reference to FIG. 24A, the anode-cathodepairs 171A-172A, 171B-172B are arranged over, but not in contact with,electrode pairs 91, 92 and corresponding solder bumps 93 arranged overan interface element (e.g., carrier substrate or submount) 94, whichpreferably includes a semiconductor wafer.

FIG. 24B shows the portion of the solid state light emitting device 186of FIG. 24A after performance of additional fabrication steps including:mounting the substrate portions 173A, 173B over the interface element 94(e.g., including making electrical connections between the anode-cathodepairs 171A-172A, 171B-172B and the electrode pairs 91, 92), thinning thesubstrate portions 173A, 173B (and simultaneously thinning the materialforming the light spreading and/or light redirecting element 177), andforming a layer of lumiphoric material 180 over primary light-emittingsurface portions 175A, 175B of the (thinned) substrate portions 173A,173B and over the light spreading and/or light redirecting element 177.In certain embodiments, a lumiphoric material layer includes a carrier(e.g., silicone) with suspended lumiphoric material (e.g., phosphorparticles), and upon curing may have a thickness of roughly 30 μm to 45μm. Operation of the solid state light emitting device 186 of FIG. 24Bis substantially similar to operation of the device 168 of FIG. 22C.

In certain embodiments, unfilled grooves or recesses defined in asubstrate may serve as light segregation elements to reduce crosstalkbetween different LEDs of a LED array. In particular, grooves orrecesses may be defined in a substrate using techniques disclosed herein(e.g., via chemical means such as etching, or mechanical means such aswire sawing). Lateral walls or boundaries of such grooves or recessesmay transmit or reflect light depending on the angle of incidence ofincoming light, such that low angle light may be reflected and highangle light may be transmitted. However, providing a lumiphoric materialover groove- or recess-defining portions of a substrate supporting a LEDarray may result in inadvertent deposition of material into the groovesor recesses, thereby interfering with light segregation utility.Techniques to overcome this issue are addressed in FIGS. 25A-25D andFIGS. 26A and 26B.

FIGS. 25A-25D illustrate a solid state light emitting device 188 (e.g.,a multi-LED chip) in different states of fabrication, in which aremovable material is provided in a recess or groove defined in asubstrate during fabrication and subsequently removed to yield anunfilled recess or groove between substrate portions. A removablematerial may be removed by at least one of chemical, mechanical, orthermal means. As one non-limiting example, a removable material may bewater-soluble (e.g., HogoMax material available from Disco Corporation,Tokyo, Japan), and may be removed by exposure to water optionally aidedby sonication, whereby the removable material may be removed fromexposed edges of a substrate via grooves or recesses extending to theexposed edges.

As shown in FIG. 25A, the solid state light emitting device 188 (e.g., amulti-LED chip) includes two LEDs 10A, 10B separated by a recess orgroove that is filled with a removable material 189. Substrate portions173A, 173B are provided with excess thickness to prevent warping orbowing, and thereby enhance the likelihood of successful electricalconnection of each LED in an array to the interface element 94. Each LED10A, 10B includes an anode-cathode pair 171A-172A, 171B-172B proximateto a functional stack 170A, 170B that is arranged to emit light into thesubstrate portion 173A, 173B that includes lateral surfaces 174A, 174B(i.e., including lateral surfaces bounding the filled recess or groove).In certain embodiments, the functional stacks 170A, 170B and/orsubstrate portions 173A, 173B of different LEDs 10A, 10B may beintegrally formed and/or connected via at least one interconnect 170′;alternatively, each LED 10A, 10B may be physically and/or electricallydisconnected relative to one another. With continued reference to FIG.25A, the anode-cathode pairs 171A-172A, 171B-172B are mounted (e.g., viasolder bumps 93) to electrode pairs 91, 92 of the interface element 94,which preferably includes a semiconductor wafer. Although solder bumps93 are shown, it is to be appreciated that any suitable electricalconnection means (e.g., solder paste or other means) may be usedinstead. FIG. 25A further shows addition of an underfill material 99(e.g., optionally including an epoxy filled with SiO₂ microspheres)between the solid state light emitting device 188 and the interfaceelement 94, whereby the underfill material 99 may provide structuralsupport between the foregoing elements without compromising conductiveelectrical connections between the anode-cathode pairs 171A-172A,171B-172B and the electrode pairs 91, 92 of the interface element 94.

FIG. 25B shows the solid state light emitting device 188 of FIG. 25Afollowing thinning (e.g., via polishing) of the substrate portions 173A,173B to enhance light extraction, yielding primary light-emittingsurface portions 175A, 175B. Such thinning correspondingly reduces theheight of the removable material 189 provided between the substrateportions 173A, 173B. FIG. 25C shows the solid state light emittingdevice 188 of FIG. 25B following formation of a layer of lumiphoricmaterial 180 over the primary light-emitting surface portions 175A, 175Bof the thinned substrate portions 173A, 173B as well as over theremovable material 189. FIG. 25D shows the solid state light emittingdevice 188 of FIG. 25C following removal of the removable material toyield an unfilled recess or groove 179 that is covered with the layer oflumiphoric material 180. The unfilled recess or groove 179 preferablyserves as a light segregating element to prevent or limit crosstalkbetween the LEDs 10A, 10B in operation. Operation of the solid statelight emitting device 188 is substantially similar to operation of thesolid state light emitting device 168 of FIG. 22C.

Although FIG. 25D shows the unfilled recess or groove 179 as extendingthrough the entire thickness of the substrate portions 173A, 173B, inalternative embodiments, a removable material may be initially formed ina bottom portion of a recess or groove and followed thereafter with alight-transmissive material to form a light spreading or lightredirecting element, whereby the light-transmissive material is notintended to be removed. The resulting structure may include an unfilledlower portion of a recess or groove to provide light segregationutility, and an upper portion of the recess or groove to provide lightspreading or light redirecting utility.

FIGS. 26A and 26B illustrate a portion of a solid state light emittingdevice 190 (e.g., a multi-LED chip) utilizing a lumiphoric material film180′ and an adhesion promoting material 191 to dispense with the needfor adding and thereafter removing a removable material as described inconnection with FIGS. 25A-25D. Referring to FIG. 26A, the solid statelight emitting device 190 includes two LEDs 10A, 10B separated by anunfilled recess or groove 179. Each LED 10A, 10B includes ananode-cathode pair 171A-172A, 171B-172B proximate to a functional stack170A, 170B that is arranged to emit light into a substrate portion 173A,173B that includes lateral surfaces 174A, 174B (i.e., including lateralsurfaces bounding the unfilled recess or groove 179) and primarylight-emitting surface portions 175A, 175B. In certain embodiments, thefunctional stacks 170A, 170B and/or substrate portions 173A, 173B ofdifferent LEDs 10A, 10B may be integrally formed and/or connected via atleast one interconnect 170′; alternatively, each LED 10A, 10B may bephysically and/or electrically disconnected relative to one another.With continued reference to FIG. 26A, the anode-cathode pairs 171A-172A,171B-172B are mounted (e.g., via solder bumps 93) to electrode pairs 91,92 of an interface element 94, which preferably includes a semiconductorwafer. FIG. 26A further shows addition of an underfill material 99(e.g., optionally including an epoxy filled with SiO₂ microspheres)between the solid state light emitting device 190 and the interfaceelement 94, whereby the underfill material 99 may provide structuralsupport between the foregoing elements without compromising conductiveelectrical connections between the anode-cathode pairs 171A-172A,171B-172B and the electrode pairs 91, 92 of the interface element 94.With the mounting complete, the substrate portions 173A, 173B are shownin a thinned state (with such thinning preferably following mounting ofthe substrate portions 173A, 173B over the interface element 94). Theadhesion promoting material 191 (e.g., silicone or epoxy) is preferablyprovided in a thin layer over the primary light-emitting surfaceportions 175A, 175B of the substrate portion 173A, 173B. FIG. 26B showsthe solid state light emitting device 190 of FIG. 26A following adhesionof the lumiphoric material film 180′ over the substrate portions 173A,173B using the adhesion promoting material 191, thereby enclosing theunfilled recess or groove 179. The unfilled recess or groove 179preferably serves as a light segregating element to prevent or limitcrosstalk between the LEDs 10A, 10B in operation. Operation of the solidstate light emitting device 188 is substantially similar to operation ofthe solid state light emitting device 168 of FIG. 22C, and the solidstate light emitting device 190 of FIG. 25D.

In certain embodiments, each layer and/or substrate (including theepitaxial region) of a multi-LED chip as disclosed herein may includefeatures that are etched, ground, sawed, formed on and/or deposited inor on one or more portions of the device chip to from pixelated regionsof the LED chip with the desired optical characteristics and/orperformance of the LED chip. Layers and/or substrates that areadditional to or different from those expressly described may beincluded with additional features. For example, additional opticalcoupling layers may be provided, such as coupling layers with index ofrefraction values that would promote light extraction from portions ofpixelated regions of a LED chip covered with such layer(s), such as inan inner or central region of each pixel. In another example, anadhesive layer (such as adhesive layer 191 illustrated in FIGS.26A-26N), can also serve that purpose or additional layers can be usedto provide optical, adhesive, structural, and/or passivation utility.Other light extraction and/or light shaping can be provided on orassociated with pixel regions to provide a desired optical performance.In certain embodiments, if a layer or substrate includes such featureson a first side thereof, then a first side of layer or substrate may bebonded to an adjacent (e.g., underlying or overlying depending on theorientation) other layer or substrate to achieve a desired opticalperformance. After such bonding is complete, additional processing canbe performed on an opposing second side of the layer or substrate, withnon-limiting examples of such additional processing steps including asgrinding, etching, sawing, defining additional optical features, and/orthinning the layer or substrate, to enhance (e.g. expose or define)and/or cooperate with features on the first side. Additional featurescan also be deposited or formed on the second side, either before orafter processing of the second side. As such, different cumulativeshapes and/or optical characteristics for the optical features can beprovided to frame or border the pixel regions of the LED chip, and/or toaffect any desired areas of each pixel region to obtain desired opticalcharacteristics. Such characteristics may be provided in or on onelayer, or may be provided by deposition or stacking of additional and/ordifferent layer(s) or substrate(s), including the same and/or differentmaterials. In certain embodiments, desired optical characteristics(e.g., desired homogeneity and contrast) may change depending on the enduse application.

While certain embodiments disclosed herein include different heightportions of a recess or groove containing materials providing differentutilities (e.g., light segregating utility versus light spreading and/orlight redirecting utility), in other embodiments, different widthportions of a recess or groove between substrate portions may containdifferent materials. One example of such an embodiment is shown in FIGS.27A and 27B. FIG. 27A illustrates a portion of a solid state lightemitting device 194 (e.g., a multi-LED chip) including three LEDs10A-10C and a substrate following performance of certain fabricationsteps, with recesses or grooves 179A-179C being defined in portions ofthe substrate between adjacent LEDs 10A-10C to define substrate portions173A-173C. (A fourth substrate portion 173Z is shown to laterally boundor define the recess or groove 179A.) Each recess or groove 179A-179Cinclude a first width portion 179A1, 17961, 179C1 and a second widthportion 179A2, 179B2, 179C2. As shown in FIG. 27A, the first widthportion 179A1, 17961, 179C1 of each recess or groove 179A-179C containsa light segregation element 176A-176C. These light segregation elements176A-176C may be formed, for example, by orienting the substratesvertically in a fluid bath, and circulating fluid containing particulatematerial to deposit particulate material in the recesses or grooves179A-179C. Other methods may be used to deposit a light segregationmaterial in the first width portion 179A1, 179B1, 179C1 of each recessor groove 179A-179C.

As shown in FIG. 27A, each LED 10A-10C includes an anode-cathode pair171A-172A, 171B-172B, 171C-172C proximate to a functional stack170A-170C that is arranged to emit light into a substrate portion173A-173C that includes lateral surfaces 174A-174C (i.e., includinglateral surfaces bounding respective recesses or grooves 179A-179C) andprimary light-emitting surface portions 175A-175C. In certainembodiments, the functional stacks 170A-170C and/or substrate portions173A-173C of different LEDs 10A-10C may be integrally formed and/orconnected via at least one interconnect 170′; alternatively, each LED10A-10C may be physically and/or electrically disconnected relative toone another.

FIG. 27B shows the solid state light emitting device 194 of FIG. 27Afollowing addition of a light-transmissive material to each second widthportion 179A2, 179B2, 179C2 of the recesses or grooves (179A-179C; shownin FIG. 27A) to form light spreading and/or light redirecting elements177A-177C that serve to reduce the appearance of non-illuminated or darkregions produced by the light segregation elements 176A-176C incomparison to an alternative configuration with each light segregationelement 176A-176C occupying a full width of a corresponding lightspreading and/or light redirecting element 177A-177C.

In certain embodiments, one or more optical elements such as awavelength-selective light-transmissive region (e.g., an optical filteror optical reflector) or a one-way mirror may be provided betweendifferent solid state emitter substrate portions to promote spreading oflight between pixels of a LED array, and therefore enhance homogeneityof combined emissions. An example is described in connection with FIGS.28A-28D, which illustrate use of optical elements arranged along sidesurfaces of solid state emitter substrate portions.

FIG. 28A is a side cross-sectional view of three LEDs 10A-10C eachincluding a substrate portion 173A-173C and each being mounted along alateral surface 174A-174C thereof to a carrier 195. Each LED 10A-10Cincludes an anode-cathode pair 171A-172A, 171B-172B, 171C-172C proximateto a functional stack 170A-170C that is arranged to emit light into thesubstrate portion 173A-173C that includes lateral surfaces 174A-174C(i.e., including lateral surfaces bounding respective recesses orgrooves) and primary light-emitting surface portions 175A-175C. Mountingof the LEDs 10A-10C to the carrier 195 is intended to enable formationof optical elements 196A-196C along side surfaces of the LEDs 10A-10C,as shown in FIG. 28B. Thereafter, the LEDs 10A-10C may be removed fromthe carrier 195 and (following placement using precision pick-and-placetechniques or the like) mounted over an interface element 94 to form asolid state light emitting device 200, as shown in FIG. 28C. Inparticular, the substrate portions 173A-173C may be mounted over theinterface element 94 with simultaneous formation of electricalconnections between the anode-cathode pairs 171A-172A, 171B-172B,171C-172C of the LEDs 10A-10C and corresponding electrode pairs 91, 92of the interface element 94 (e.g., using solder bumps 93, solder paste,or similar means). Additionally, light-transmissive material may bedeposited into gaps between the optical elements 196A-196C and lateralsurfaces 174A-174C of adjacent LEDs 10A-10C to form light spreadingand/or light redirecting elements 197A-197C. Thereafter, the primarylight-emitting surface portions 175A-175C, the optical elements196A-196C, and the light spreading and/or light redirectingelements197A-197C are overlaid with a layer of lumiphoric material 180,as shown in FIG. 28D.

In operation of the solid state light emitting device 200, current issupplied to the LEDs 10A-10C via the anode-cathode pairs 171A-172A,171B-172B, 171C-172C and LED emissions are generated in the functionalstacks 170A-170C. Such LED emissions are propagated through thesubstrate portions 173A-173C, with a majority of steep angle emissionsimpinging on the layer of lumiphoric material 180 above the primarylight-emitting surface portions 175A-175C. Shallow angle LED emissionsmay be transmitted (optionally in combination with refraction) orreflected between substrate portions 173A-173C via the optical elements196A-196C, but preferably, at least a fraction of any LED emissionsinteracting with the optical elements 196A-196C may be directed throughthe light spreading and/or redirection elements 197A-197C to impinge onthe overlying lumiphoric material 180. In this manner, appearance of anon-illuminated or dark zone between the substrate portions 173A-173C ispreferably reduced, and homogeneity of light emissions of the lightemitting device may be enhanced.

In certain embodiments, light-transmissive portions of at least onesubstrate include at least one beveled edge to enhance spreading oflight over light segregation elements and therefore serve as inter-pixellight spreading regions. In certain embodiments, multiple inter-pixellight spreading regions are formed in a multi-LED chip. An angular rangeof the at least one beveled edge may be adjusted to optimize lightextraction. Examples of such a configuration are shown in connectionwith FIGS. 29A and 29B and FIGS. 30A and 30B.

FIGS. 29A and 29B illustrate a portion of a solid state light emittingdevice 202 (e.g., a multi-LED chip) including two LEDs 10A, 10B and asubstrate (including substrate portions 173A, 173B) defining a recess orgroove 179 containing a light segregation element 176, and with thesubstrate portions 173A, 173B including beveled edge portions 204A, 204Barranged proximate to the light segregation element 176. In certainembodiments, the recess or groove 179 may be formed with a wire saw, andthe beveled edge portions 204A, 204B may be formed with a wire sawarranged to travel in each instance in an angled direction. The bevelededge portions 204A, 204B laterally bound an expanded recess portion 179′having a greater width than the recess or groove 179 containing thelight segregation element 176. Each LED 10A, 10B includes ananode-cathode pair 171A-172A, 171B-172B proximate to a functional stack170A, 170B that is arranged to emit light into the substrate portion173A, 173B that includes lateral surfaces 174A, 174B (i.e., includinglateral surfaces bounding the recess or groove 179) and primarylight-emitting surface portions 175A, 175B. In certain embodiments, thefunctional stacks 170A, 170B and/or substrate portions 173A, 173B ofdifferent LEDs 10A, 10B may be integrally formed and/or connected via atleast one interconnect 170′; alternatively, each LED 10A, 10B may bephysically and/or electrically disconnected relative to one another.FIG. 29B shows the solid state light emitting device 202 of FIG. 29Afollowing formation of a layer of lumiphoric material 180 over thesubstrate portions 173A, 173B and the light segregation element 176.

In operation of the solid state light emitting device 202, current issupplied to the LEDs 10A, 10B via the anode-cathode pairs 171A-172A,171B-172B and LED emissions are generated in the functional stacks 170A,170B. Such LED emissions are propagated through the substrate portions173A, 173B, with a majority impinging on the layer of lumiphoricmaterial 180 above the primary light-emitting surface portions 175A,175B. Shallow angle LED emissions are blocked from transmission betweensubstrate portions 173A, 173B by the light segregation element 176;however, a fraction of moderate angle emissions may transit through thebeveled edge portions 204A, 204B (serving as light spreading and/orlight redirecting regions) to impinge on a portion of the lumiphoricmaterial 180 within the expanded recess portion 179′ and registered with(or proximate to) the light segregation element 176. In this manner, aregion forward of the light segregation element 176 (corresponding to aninter-pixel light spreading region 203) is illuminated, appearance of anon-illuminated or dark zone between the substrate portions 173A, 173Bis reduced, and homogeneity of light emissions of the solid state lightemitting device 202 is enhanced.

FIGS. 30A and 30B illustrate another beveled edge embodiment thatincludes an unfilled recess or groove serving as a light segregationelement and that is arranged to be covered with a lumiphoric materialfilm. Referring to FIG. 30A, a solid state light emitting device 205(e.g., a multi-LED chip) includes two LEDs 10A, 10B separated by anunfilled recess or groove 179. Each LED 10A, 10B includes ananode-cathode pair 171A-172A, 171B-172B proximate to a functional stack170A, 170B that is arranged to emit light into a substrate portion 173A,173B that includes lateral surfaces 174A, 174B (i.e., including lateralsurfaces bounding the unfilled recess or groove 179) and primarylight-emitting surface portions 175A, 175B. The substrate portions 173A,173B include beveled edge portions 204A, 204B arranged proximate to theunfilled recess or groove 179. The beveled edge portions 204A, 204Blaterally bound an expanded recess portion 179′ having a greater widththan the recess or groove 179. In certain embodiments, the functionalstacks 170A, 170B and/or substrate portions 173A, 173B of different LEDs10A, 10B may be integrally formed and/or connected via at least oneinterconnect 170′; alternatively, each LED 10A, 10B may be physicallyand/or electrically disconnected relative to one another. As shown, theanode-cathode pairs 171A-172A, 171B-172B are mounted (e.g., via solderbumps 93 or other means, such as solder paste or the like) to electrodepairs 91, 92 of an interface element 94, which preferably includes asemiconductor wafer. Additionally, an underfill material 99 is providedbetween the solid state light emitting device 205 and the interfaceelement 94.

Referring to FIG. 30B, an adhesion promoting material 191 (e.g.,silicone or epoxy) is preferably provided in a thin layer over theprimary light-emitting surface portions 175A, 175B of the substrateportions 173A, 173B, and a lumiphoric material film 180′ is adhered overthe adhesion promoting material 191, thereby enclosing the unfilledrecess or groove 179 and the expanded recess portion 179′. The unfilledrecess or groove 179 preferably serves as a light segregating element toprevent or limit crosstalk between the LEDs 10A, 10B in operation, andthe beveled edge portions 204A, 204B preferably serve as light spreadingand/or light redirecting elements to cause LED emissions to impinge on aportion of the lumiphoric material film 180′ overlying the expandedrecess portion 179′. In this manner, a region forward of the unfilledrecess or groove 179 (with the forward region corresponding to aninter-pixel light spreading region 203) is illuminated, appearance of anon-illuminated or dark zone between the substrate portions 173A, 173Bis reduced, and homogeneity of light emissions of the solid state lightemitting device 205 is enhanced.

In certain embodiments, light segregation elements may be definedbetween portions of a substrate of a multi-LED array (e.g., embodied ina multi-LED chip), a lumiphoric material layer may be arranged over thesubstrate portions, and a light-transmissive secondary substrateincluding light spreading and/or light redirecting regions may bearranged over the lumiphoric material layer to reduce the appearance ofnon-illuminated or dark zones overlying light segregation elements. Thelight-transmissive secondary substrate may include a patternablewafer-type material such as sapphire, and the light spreading and/orlight redirecting regions may be defined by photolithographic patterningand selective material removal, optionally followed by selectivematerial deposition (e.g., to deposit material having lumiphoricmaterial and/or a different index of refraction, scattering, or opticalproperties relative to the bulk of the light-transmissive secondarysubstrate). Examples of such embodiments are described in connectionwith FIGS. 31-35.

FIG. 31 illustrates a portion of a solid state light emitting device 206(e.g., a multi-LED chip) including three LEDs 10A-10C and a substrate,with recesses or grooves being defined in portions of the substratebetween adjacent LEDs 10A-10C to define substrate portions 173A-173C.Each recess or groove is filled with a light segregation element 176A,176B. Each LED 10A-10C includes an anode-cathode pair 171A-172A,171B-172B, 171C-172C proximate to a functional stack 170A-170C that isarranged to emit light into the substrate portion 173A-173C thatincludes lateral surfaces 174A-174C (i.e., including lateral surfacesbounding respective recesses or grooves) and primary light-emittingsurface portions 175A-175C. In certain embodiments, the functionalstacks 170A-170C and/or substrate portions 173A-173C of different LEDs10A-10C may be integrally formed and/or connected via at least oneinterconnect 170′; alternatively, each LED 10A-10C may be physicallyand/or electrically disconnected relative to one another. A layer oflumiphoric material 180 is arranged over the primary light-emittingsurface portions 175A-175C and light segregation elements 176A, 176B. Asecondary substrate 210 is arranged over the layer of lumiphoricmaterial 180 and includes triangular light spreading and/or lightredirecting regions 214A, 214B in the secondary substrate 210 proximateto the layer of lumiphoric material 180. The secondary substrate 210includes a lower surface 211 and an upper surface 212, with the lowersurface proximate to the layer of lumiphoric material 180. Each lightspreading and/or light redirecting region 214A, 214B includes a base215A, 215B and an apex 216A, 216B, wherein the base 215A, 215B is closerthan the apex 216A, 216B to the substrate portions 173A-173C such thateach apex 216A, 216B points upward. A light scattering material 208 isfurther arranged over the upper surface 212 of the secondary substrate210.

In operation of the solid state light emitting device 206, current issupplied to the LEDs 10A-10C via the anode-cathode pairs 171A-172A,171B-172B, 171C-172C and LED emissions are generated in the functionalstacks 170A-170C. Such LED emissions are propagated through thesubstrate portions 173A-173C, with a majority of steep angle emissionsimpinging on the layer of lumiphoric material 180 above the primarylight-emitting surface portions 175A-175C. Shallow angle LED emissionsmay be reflected by the light segregation elements 176A, 176B andredirected upward toward the lumiphoric material 180. A portion of thelumiphoric material 180 between substrate portions 173A-173C isconfigured to direct emissions into the light spreading and/or lightredirecting regions 214A, 214B. In this manner, regions forward of thelight segregation elements 176A, 176B (corresponding to inter-pixellight spreading regions 207A, 207B) are illuminated, appearance ofnon-illuminated or dark zones between the substrate portions 173A-173Ccorresponding to the light segregation elements 164A, 176B is reduced,and homogeneity of light emissions of the solid state light emittingdevice 206 is enhanced.

FIG. 32 illustrates a portion of another solid state light emittingdevice 220 (e.g., a multi-LED chip) that is substantially similar to thesolid state light emitting device 206 of FIG. 31 (such that identicalelements will not be described again), but with differently shaped anddifferently placed light spreading and/or light redirecting regions218A, 218B. In particular, the secondary substrate 210 arranged over alayer of lumiphoric material film 180′ includes rectangular lightspreading and/or light redirecting regions 218A, 218B in the secondarysubstrate 210 that extend through the layer of lumiphoric material film180′ (such that the layer may be discontinuous in character) and throughlower portions of the secondary substrate 210 (e.g., through the lowersurface 211 of the secondary substrate 210 but not to the upper surface212). Each light spreading and/or light redirecting region 218A, 218B isregistered with an underlying light segregation element 176A, 176B andincludes a width that is substantially the same as the correspondingunderlying light segregation element 176A, 176B. Operation of the solidstate light emitting device 220 is substantially similar to operation ofthe solid state light emitting device 206 of FIG. 31.

FIG. 33 illustrates a portion of another solid state light emittingdevice 222 (e.g., a multi-LED chip) that is substantially similar to thesolid state light emitting device 206 of FIG. 31 (such that identicalelements will not be described again), but with differently placed andoriented light spreading and/or light redirecting regions 224A, 224B. Inparticular, the secondary substrate 210 arranged over a layer oflumiphoric material 180 includes triangular light spreading and/or lightredirecting regions 224A, 224B in the secondary substrate 210 that areproximate to an upper surface 212 of the secondary substrate 210. Eachlight spreading and/or light redirecting region 224A, 224B includes abase 225A, 225B and an apex 226A, 226B, wherein the apex 226A, 226B iscloser than the base 225A, 225B to the substrate portions 173A-173C,such that each apex 226A, 226B points downward. A light scatteringmaterial 208 is further arranged over an upper surface of the secondarysubstrate 210, with the base 225A, 225B of each light spreading and/orlight redirecting region 224A, 224B extending upward through at least aportion of the light scattering material 208. Operation of the solidstate light emitting device 220 is substantially similar to operation ofthe solid state light emitting device 206 of FIG. 31.

FIG. 34 illustrates a portion of another solid state light emittingdevice 228 (e.g., a multi-LED chip) that is substantially similar to thesolid state light emitting device 206 of FIG. 31 (such that identicalelements will not be described again), but with differently placed andoriented light spreading and/or light redirecting regions 224A, 224B andlengthened light segregation elements 176′A, 176′6. In particular, eachlengthened light segregation element 176′A, 176′B extends upward pastsubstrate portions 173A-173C and through at least a portion of a layerof lumiphoric material film 180′. Additionally (in a manner similar toFIG. 33), a secondary substrate 210 arranged over the layer oflumiphoric material film 180′ includes triangular light spreading and/orlight redirecting regions 224A, 224B in the secondary substrate 210 thatare proximate to an upper surface 212 of the secondary substrate 210.Each light spreading and/or light redirecting region 224A, 224B includesa base 225A, 225B and an apex 226A, 226B, wherein the apex 226A, 226B iscloser than the base 225A, 225B to the substrate portions 173A-173C,such that each apex 226A, 226B points downward. A light scatteringmaterial 208 is further arranged over an upper surface of the secondarysubstrate 210, with the base 225A, 225B of each light spreading and/orlight redirecting region 224A, 224B extending upward through at least aportion of the light scattering material 208. Operation of the solidstate light emitting device 220 is substantially similar to operation ofthe solid state light emitting device 206 of FIG. 31.

FIG. 35 illustrates a portion of another solid state light emittingdevice 230 (e.g., a multi-LED chip) that is substantially similar to thedevice 206 of FIG. 31 and the device 220 of FIG. 32 (such that identicalelements will not be described again), but with differently placed,dimensioned, and oriented light spreading and/or light redirectingregions 232A, 232B. A secondary substrate 210 arranged over a layer oflumiphoric material film 180′ includes rectangular light spreadingand/or light redirecting regions 232A, 232B in the secondary substrate210 that extend through the layer of lumiphoric material film 180′ (suchthat the layer of lumiphoric material film 180′ may be discontinuous incharacter) and through lower portions of the secondary substrate 210(i.e., extending through the lower surface 211 of the secondarysubstrate 210 but not far enough to contact the upper surface 212). Eachlight spreading and/or light redirecting region 232A, 232B is registeredwith an underlying light segregation element 176A, 176B, but includes awidth that is substantially smaller than the corresponding underlyinglight segregation element 176A, 176B. Operation of the solid state lightemitting device 230 is substantially similar to operation of the solidstate light emitting device 206 of FIG. 31, and solid state lightemitting device 220 of FIG. 32.

FIG. 36 shows interconnections between a circuit board 240 and asubmount 250 of a test apparatus for operating a solid state lightemitting device (e.g., a multi-LED chip) including a high density LEDarray as disclosed herein. The circuit board 240 includes a substrate241 (e.g., including conventional circuit board material such as FR-4)supporting numerous (e.g., copper) electrical traces 243, which may beformed on one or both sides thereof, and/or may be formed in sequentiallayers with intervening dielectric layers (not shown). The circuit board240 supports multiple interconnects, including four interconnects242A-242D that are configured to receive ribbon cables 244A-244D forcommunicating signals with interconnects 252A-252D of the submount 250.The submount 250 preferably comprises a semiconductor wafer 251 havingincluding multiple traces 253 arranged thereon. A rectangular arraymounting area 255 is configured to receive an array of LEDs, andpreferably permits each pixel (LED) of the array of LEDs to beindividually controlled, such as by providing one anode and one cathodeper LED.

FIGS. 37A and 37B depict another submount 260 including a semiconductorwafer 261 supporting multiple electrical traces 263 that are routed to arectangular array mounting area 265 configured to receive an array ofLEDs (not shown) as disclosed herein. The traces 263 extend to multiplecontacts 262 proximate to one edge of the submount 260. The submount 260is useable as a test apparatus, such that within the rectangular arraymounting area 265, only selected contact pairs 266 (e.g., arranged in aroughly diagonal direction within the pictured dashed line shape) areactive and capable of operating LEDs of a LED array. Additional activecontact pairs would be necessary to operate every pixel in a LED arrayoccupying the entire rectangular array mounting area 265. In certainembodiments, active contact pairs may be arranged along an accessiblesurface of an applicant specific integrated circuit (ASIC) chipconfigured to receive a LED array as disclosed herein. FIG. 38A is amagnified portion of the submount 260 of FIGS. 37A and 37B, showing thetraces 263 and rectangular array mounting area 265 arranged over thesemiconductor wafer 261, and the selected contact pairs 266 that areoperational (within the pictured dashed line shape).

FIG. 39A is a side cross-sectional schematic assembly view of a portionof a solid state light emitting device including two flip chip LEDs 10A,10B (e.g., Cree EZ-series flip chips available from Cree, Inc., Durham,N.C.) arranged to transmit LED emissions through light-transmissivesubstrate portions 273A, 273B that are separated by a recess or groove279. Each LED 10A, 10B includes an anode-cathode pair 271A-272A,271B-272B proximate to a functional stack 270A, 270B that is arranged toemit light into the substrate portions 273A, 273B, with the LEDs 10A,10B optionally being embodied in a single multi-LED chip. The anodes271A, 271B have different heights relative to the cathodes 272A, 272B,and are arranged above electrodes 281A, 282A, 281B, 282B of a submount280 that preferably includes a semiconductor wafer. The electrodes 281A,282A, 281B, 282B are arranged as electrode pairs 281A-282A, 281B-282B,wherein each electrode pair includes one short electrode 281A, 281B andone tall electrode 282A, 282B, and each electrode 281A, 282A, 281B, 282Bis configured to mate with an anode 271A, 272A or cathode 271B, 272B ofcomplementary height. The electrode pairs 281A-282A, 281B-282B arearranged to receive the anode-cathode pairs 271A-272A, 271B-272B byappropriate mounting means such as solder paste, solder bumps, or thelike. Providing electrodes 281A-282A, 281B-282B of different heights mayreduce the risk of inadvertent short-circuiting between electrodes (oranodes and cathodes) of opposite polarity due to flow of excess solderpaste or solder flux during mounting, which may be of particular concernwhen the LEDs 10A, 10B have a small pixel pitch (i.e., are in closeproximity to one another).

FIG. 39B is a side cross-sectional schematic assembly view of a portionof a solid state light emitting device that is similar to the device ofFIG. 39A, but includes a modified arrangement of electrodes along asubmount. As shown, the solid state light emitting device includes twoflip chip LEDs 10A, 10B arranged to transmit LED emissions throughlight-transmissive substrate portions 273A, 273B that are separated by arecess or groove 279. Each LED 10A, 10B includes an anode-cathode pair271A-272A, 271B-272B proximate to a functional stack 270A, 270B that isarranged to emit light into the substrate portions 273A, 273B. Theanodes 271A, 271B have different heights relative to the cathodes 272A,272B, and are arranged above electrodes 291A, 292A, 291B, 292B of asubmount 290 that preferably includes a semiconductor wafer. Two of theelectrodes 292A, 292B include boundary walls 295A, 295B that arearranged to prevent lateral flow of solder material that may emanatefrom solder bumps 293 when melted during a soldering operation. Thepresence of solder bumps 293 also raises the effective height of theelectrodes 292A, 292B relative to the other electrodes 291A, 291B, whichmay be configured to receive solder paste having a thinner effectiveheight than the solder bumps 293. Electrode pairs 291A-292A, 291B-292Bare arranged to receive the anode-cathode pairs 271A-272A, 271B-272B.Providing electrodes 291A-292A, 291B-292B of different effectiveheights, in combination with providing the boundary walls 295A, 295B,may reduce the risk of inadvertent short-circuiting between electrodes(or anodes and cathodes) of opposite polarity during a mountingoperation, which may be of particular concern when the LEDs 10A, 10Bhave a small pixel pitch (i.e., are in close proximity to one another).

In certain embodiments, a solid state light emitting device (e.g., amulti-LED chip) including multiple LEDs and a substrate may be mountedover an interface element (e.g., an ASIC, or a carrier substrate orsubmount) before one or more recesses or grooves are defined in thesubstrate connecting the LEDs. Defining recesses or grooves in asubstrate tends to weaken the substrate and may affect its planarity. Bymounting the solid state light emitting device to an interface elementbefore one or more recesses or grooves are defined in the substrate, theability to ensure reliable connections therebetween may be enhanced.

FIGS. 40A-40D illustrate steps in fabricating a solid state lightemitting device 300 with features promoting improved contrast andinter-pixel homogeneity, mounted over an interface element 94 (e.g.,optionally embodied in an ASIC, or a carrier or submount), with suchmounting being performed prior to formation of grooves or recessesbetween different LEDs 10A, 10B of the solid state light emitting device300. Each LED 10A, 10B includes an anode-cathode pair 171A-172A,171B-172B proximate to a functional stack 170A, 170B that is arranged toemit light into portions of a substrate 173. The substrate 173 includeslateral surfaces 174A, 174B and a light-emitting surface that is subjectto being divided into multiple light-emitting surface portions 175A,175B. In certain embodiments, the functional stacks 170A, 170B and/orportions of the substrate 173 corresponding to different LEDs 10A, 10Bmay be integrally formed and/or connected via at least one interconnect170′; alternatively, each LED 10A, 10B may be physically and/orelectrically disconnected relative to one another. The anode-cathodepairs 171A-172A, 171B-172B are mounted (e.g., via solder bumps 93) toelectrode pairs 91, 92 of the interface element 94, which may include asemiconductor wafer. Although solder bumps 93 are shown, it is to beappreciated that any suitable electrical connection means (e.g., solderpaste or other means) may be used instead. In certain embodiments,bonding between the solid state light emitting device 300 and theinterface element 94 comprises wafer level bonding of a wafer definingmultiple multi-LED chips and a wafer or other substrate definingmultiple interface elements, with all contacts of the anode-cathodepairs 171A-172A, 171B-172B and the electrode pairs 91, 92 of theinterface element 94 being appropriately aligned prior to completion ofsteps such as grooving, filling, and singulation.

FIG. 40B shows the solid state light emitting device 300 of FIG. 40Afollowing formation of a recess or groove 179 in the substrate 173 ofFIG. 40A to form substrate portions 173A, 173B, each having acorresponding light-emitting surface portion 175A, 175B. Although only asingle recess or groove 179 and two LEDs 10A, 10B are shown, it is to beappreciated that any suitable number of LEDs separated by grooves orrecesses may be provided, with the LEDs preferably being arranged in atwo-dimensional array. In certain embodiments, the recesses or groovesmay be defined by mechanical sawing, by etching, by laser cutting, or byother methods, and the recesses or grooves may be defined through only aportion of the substrate or through the entire thickness of thesubstrate to yield the substrate portions 173A, 173B.

FIG. 40C illustrates the solid state light emitting device 300 of FIG.40B following addition of a removable (e.g., sacrificial) material 189to the recess or groove 179 (shown in FIG. 40B), and following formationof a lumiphoric material 180 over the substrate portions 173A, 173B andthe removable material 189. Optionally, an underfill material (notshown) may be arranged between the interface element 94 and the solidstate light emitting device 300.

FIG. 40D illustrates the solid state light emitting device 300 of FIG.40C following removal of the removable material 189 (shown in FIG. 40C)from between the substrate portions 173A, 173B to yield an unfilledrecess or groove 179 that is covered with the lumiphoric material 180.The unfilled recess or groove 179 preferably serves as a lightsegregating element to prevent or limit crosstalk between the LEDs 10A,10B when they are operated. Operation of the solid state light emittingdevice 300 is substantially similar to operation of the solid statelight emitting device 168 of FIG. 22C.

In certain embodiments, a solid state light emitting device (e.g., amulti-LED chip) may be mounted over a first interface element (e.g.,embodied in a carrier substrate or a submount) providing structuralsupport to the solid state light emitting device and includingpass-through electrical connections for mounting the first interfaceelement to a second interface element (e.g., embodied in an ASIC). Incertain embodiments, the pass-through electrical connections may includeelectrically conductive vias passing through an interior of the firstinterface element to provide conductive paths between contact padsdefined on opposing faces of the first interface element. In certainembodiments, a multi-LED chip may be mounted to a first interfaceelement to provide structural support for the multi-LED chip before oneor more recesses or grooves are defined therein. Such support may bebeneficial to promote handling and/or address packaging constraints,since formation of recesses or grooves may tend to cause light emittingdevices to be very fragile and susceptible to cracking.

FIG. 41 is a side cross-sectional schematic view of a solid state lightemitting device (e.g., a multi-LED chip) 304 including multiple LEDs10A, 10B and a substrate 173 mounted over a first interface element 305embodied in a carrier substrate or submount. The first interface element305 includes electrical contacts 311, 312 arranged on a first majorsurface 306, electrical contacts 315, 316 arranged on a second majorsurface 308, and electrically conductive vias 309 extending between thefirst and second major surfaces 306, 308 to provide conductive pathsbetween corresponding electrical contacts 311, 212, 315, 316. The firstinterface element 305 is positioned over a (second) interface element 94embodied in an ASIC to enable mounting of the first interface element305 between the solid state light emitting device 304 and the secondinterface element 94. The second interface element 94 includes electrodepairs 91, 92 arranged to be electrically connected to correspondingelectrical contacts 315, 316 along the second major surface 308 of thefirst interface element 305 using solder bumps 93 or other means such assolder paste (not shown). The substrate 173 is divisible into substrateportions each being associated with a different LED 10A, 10B. Each LED10A, 10B includes an anode-cathode pair 171A-172A, 171B-172B proximateto a functional stack 170A, 170B that is arranged to emit light into acorresponding one of the substrate portions, with each LED 10A, 10Bembodying a flip chip LED. In certain embodiments, the functional stacks170A, 170B and/or substrate portions of different LEDs 10A, 10B may beintegrally formed and/or connected via at least one interconnect 170′;alternatively, each LED 10A, 10B may be physically and/or electricallydisconnected relative to one another. Each substrate portion includeslateral surfaces 174A, 174B and includes a primary light-emittingsurface portion 175A, 175B. As shown, the solid state light emittingdevice 304 is devoid of any grooves or recesses between the LEDs 10A,10B, but it is to be appreciated that grooves or recesses may be definedthrough a portion of the thickness or through the entire thickness ofthe substrate173 between the LEDs 10A, 10B (to form the substrateportions), either following the mounting of the solid state lightemitting device 304 to the first interface element 305, or following themounting of the first interface element 305 (with the solid state lightemitting device 304 arranged thereon) over the second interface element94.

In certain embodiments, multiple solid state light-emitting devices(e.g., multi-chip LEDs), optionally arranged in a two-dimensional array,may be mounted over a single interface element such as an ASIC, or acarrier substrate or submount, optionally before one or more grooves orrecesses are defined in portions of substrates between LEDs of the solidstate-light emitting devices. In other embodiments, multiple interfaceelements such as ASICs, or carrier substrates or submounts, may bearranged to be mounted to a single multi-chip solid state light emittingdevice (e.g., a multi-chip LED chip), optionally before one or moregrooves or recesses are defined in portions of the multi-chip solidstate light emitting device. In certain embodiments, multiple singulatedLED arrays or multi-LED device (prior to formation of grooves orrecesses therein) may be placed and bonded to a single interface element(e.g., ASIC, or carrier substrate or submount); alternatively, in otherembodiments, a single LED array may be arranged to receive multipleplaced and bonded singulated ASIC chips.

FIG. 42 illustrates two solid state light emitting devices (e.g.,multi-LED chips) 320-1, 320-2 mounted over a single interface element(e.g., ASIC, or carrier substrate or submount) 94, prior to defining ofrecesses or grooves in substrates 173-1, 173-2 of the solid state lightemitting devices 320-1, 320-2. Although FIG. 42 illustrates the presenceof a gap 321 between the solid state light emitting devices 320-1,320-2, in certain embodiments the gap 321 may be filled with one or morematerials and/or eliminated (e.g., by causing the solid state lightemitting devices 320-1, 320-2 to abut one another without spacetherebetween). Each solid state light emitting device 320-1, 320-2includes multiple LEDs 10-1A, 10-1B, 10-2A, 10-2B, and each LED 10-1A,10-1B, 10-2A, 10-2B includes an anode-cathode pair 171-1A, 172-1B,171-2A, 172-2B proximate to a functional stack 170-1A, 170-1B, 170-2A,170-2B that is arranged to emit light into portions of a substrate173-1, 173-2. Each substrate 173-1, 173-2 is divisible (e.g., usinggrooves or recesses, not shown) into substrate portions each beingassociated with a different LED 10-1A, 10-1B, 10-2A, 10-2B. Eachsubstrate 173-1, 173-2 includes lateral surfaces 174-1A, 174-2B and aprimary light-emitting surface that is subject to being divided intomultiple light-emitting surface portions 175-1A, 175-1B, 175-2A, 175-2B.In certain embodiments, the functional stacks 170-1A, 170-1B, 170-2A,170-2B and/or portions of the substrates 173-1, 173-2 corresponding todifferent LEDs 10-1A, 10-1B, 10-2A, 10-2B may be integrally formedand/or connected via at least one interconnect 170′-1, 170′-2;alternatively, each LED 10-1A, 10-1B, 10-2A, 10-2B may be physicallyand/or electrically disconnected relative to one another. Theanode-cathode pairs 171-1A, 172-1B, 171-2A, 172-2B are mounted (e.g.,via solder bumps 93) to electrode pairs 91, 92 of the interface element94, which may include a semiconductor wafer. In certain embodiments, thesolid state light emitting devices 320-1, 320-2 may be processed aftermounting to the interface element 94, such as to thin the entiresubstrates 173-1, 173-2 and/or to define recesses or grooves in thesubstrates 173-1, 173-2 between the LEDs 10-1A, 10-1B, 10-2A, 10-2B,such as in locations marked by dashed arrows 322-1, 322-2.

FIG. 43 illustrates a solid state light emitting device (e.g., amulti-LED chip) 330 mounted over multiple interface elements 94-1, 94-2(e.g., ASICs, or carrier substrates or submounts), prior to defining ofrecesses or grooves in a substrate 173 connecting multiple LEDs 10A-10Dof the solid state light emitting device 330. Each LED 10A-10D includesan anode (e.g., anode 171A) and a cathode (e.g., cathode 172D) proximateto a functional stack 170A-170D that is arranged to emit light intoportions of the substrate 173, which is divisible into substrateportions each associated with a different LED 10A-10D. In particular,the substrate 173 may be divided by defining recesses or grooves (notshown) through a portion of the thickness or an entire thickness of thesubstrate 173 generally between the LEDs 10A-10D, such as in locationsmarked by dashed arrows 332A-332C. The substrate 173 includes lateralsurfaces 174A, 174D and a primary light-emitting surface that is subjectto being divided into multiple light-emitting surface portions175A-175D. In certain embodiments, the functional stacks 170A-170Dand/or portions of the substrate 173 corresponding to different LEDs10A-10D may be integrally formed and/or connected via at least oneinterconnect 170′; alternatively, each LED 10A-10D may be physicallyand/or electrically disconnected relative to one another. Theanode-cathode pairs (e.g., including anode 171A through cathode 172D)are mounted (e.g., via solder bumps 93) to electrode pairs 91-1, 92-1,91-2, 92-2 of the interface elements 94-1, 94-2, which may includesemiconductor wafers. In certain embodiments, the solid state lightemitting device 330 may be processed after mounting to the interfaceelements 94-1, 94-2, such as to thin the entire substrate 173, and/or todefine recesses or grooves in the substrate 173 between the LEDs10A-10D.

In certain embodiments, epitaxial layer portions including active layersof a solid state light emitting device (e.g., a multi-LED chip) may beselectively removed prior to mounting of the solid state light emittingdevice to an interface element, such as an ASIC, or a carrier substrateor a submount. Such selective removal may be accomplished by etching,sawing, or other means, and may optionally be followed by selectiveremoval of substrate material extending through a partial or entirethickness of a substrate supporting the epitaxial layers. In certainembodiments, epitaxial layer portions may be selectively removed betweenLEDs, which may be desirable to enable independent operation of, and/orreduced thermal communication between, different LEDs. In certainembodiments, one or more first recesses or grooves may be defined in afirst direction (e.g., from a front side) through epitaxial layerportions of a solid state light emitting device, followed by mounting ofthe solid state light emitting device over an interface element,followed by defining of one or more second recesses or grooves in asecond direction (e.g., from a back side) through substrate portions ofthe solid state light emitting device. In certain embodiments, the firstrecesses or grooves may be registered with the second recesses orgrooves, optionally in a manner to cause the first recesses to mergewith the second recesses, or alternatively to leave a thin membraneportion of the substrate to separate the first recesses and the secondrecesses.

FIGS. 44A-44C illustrate steps in fabricating a solid state lightemitting device (e.g., a multi-LED chip) 340 with features promotingimproved contrast and inter-pixel homogeneity, mounted over an interfaceelement 94 (e.g., optionally embodied in an ASIC, or a carrier orsubmount), with a first recess or groove 341 being defined in the solidstate light emitting device 340 in a first direction prior to mounting.

FIG. 44A illustrates the solid state light emitting device (e.g.,multi-LED chip) 340 including the first (front side) recess or groove341. The first recess or groove 341 extends through epitaxial layersforming functional stacks 170A, 170B of different LEDs 10A, 10B of thesolid state light emitting device 340. The functional stacks 170A, 170Bare arranged between a substrate 173 and anode-cathode pairs 171A-172A,171B-172B of the LEDs 10A, 10B, with the functional stacks 170A, 170Bbeing arranged to emit light into portions of the substrate 173 to exitthrough primary light-emitting surface portions 175A, 175B of thesubstrate 173 bounded between lateral surfaces 174A, 174B. As shown, thefirst recess or groove 341 is defined (e.g., by etching or other means)through epitaxial layers to separate the functional stacks 170A, 170B.

FIG. 44B illustrates the solid state light emitting device 340 of FIG.44A after being mounted over an interface element (e.g., ASIC, orcarrier substrate or submount) 94. A dashed arrow 342A identifies alocation where a second recess (not shown) may be defined through atleast a portion of the substrate 173. The anode-cathode pairs 171A-172A,171B-172B of the solid state light emitting device 340 are mounted(e.g., via solder bumps 93) to electrode pairs 91, 92 of the interfaceelement 94, which may include a semiconductor wafer. Although solderbumps 93 are shown, it is to be appreciated that any suitable electricalconnection means (e.g., solder paste or other means) may be usedinstead.

FIG. 44C illustrates the solid state light emitting device 340 of FIG.44B after addition of an underfill material 345 between the solid statelight emitting device 340 and the interface element 94, and formation ofa second recess or groove 343 defined (i.e., in a second directionopposing a first direction in which the first recess or groove 341 wasformed) through a portion of the substrate to yield substrate portions173A, 173B. As shown, the second recess or groove 343 is registered(i.e., aligned) with the first recess or groove 341, but the respectiverecesses or grooves 341, 343 are separated by a thin membrane region 344of the substrate 173.

FIG. 44D illustrates a solid state light emitting device 340′ that issubstantially similar to the device 340 shown in FIG. 44C (wherebyelements with the same reference numerals will not be described again),but including a second alternate recess or groove 346 that extendsthrough an entire thickness of the substrate portions 173A, 173B (i.e.,to expose a portion of the underfill material 345 arranged generallybetween the solid state light emitting device 340′ and the interfaceelement 94).

FIG. 45 illustrates a solid state light emitting device (e.g., amulti-LED chip) 350 including recesses or grooves defined betweenadjacent LEDs 10A-10C, and with different emitter regions 351-353 havingdifferent characteristics. Each LED 10A-10C includes an anode-cathodepair 171A-172A, 171B-172B, 171C-172C proximate to a functional stack170A-170C that is arranged to emit light into substrate portions173A-173C. Recesses or grooves are defined between respective LEDs10A-10C to yield lateral surfaces 174A-174C between the respective LEDs10A-10C, and to yield beveled edge portions 204A, 204B-1, 204B-2, 204Calong lateral boundaries of substrate portions 173A-173C to providelight segregation and inter-pixel light spreading utilities. Primarylight emitting surfaces of the substrate portions 173A-173C for therespective LEDs 10A-10C are covered with adhesion promoting material 191(e.g., epoxy) and a layer of lumiphoric material 180 that spans aboveand between each LED 10A-10C. In certain embodiments, the functionalstacks 170A-170C and/or substrate portions 173A-173C of different LEDs10A-10C may be integrally formed and/or connected via at least oneinterconnect 170′; alternatively, each LED 10A-10C may be physicallyand/or electrically disconnected relative to one another. A lightreflecting coating 355A, 355C may be provided proximate to lateral edgesof substrate portions 173A, 173C that are arrangeable along lateraledges of a solid state light emitting apparatus. Properties of differentemitter regions 351-353 may be tailored to provide differentcharacteristics (e.g., directionality, lateral cutoff, beam pattern,color point, color temperature, intensity, etc.) such as may be usefuldepending on relative positioning of the emitter regions 351-353 in asolid state light emitting apparatus.

Embodiments disclosed herein may provide one or more of the followingbeneficial technical effects: enabling fabrication of solid state lightemitting devices with small pixel pitch emitter arrays; providing smallpixel pitch solid state light emitting devices (includinglumiphor-containing emitting devices) with reduced scattering and/oroptical crosstalk properties; providing small pixel pitch solid statelight emitting devices (including lumiphor-containing emitting devices)with enhanced uniformity of illumination while simultaneously providingreduced optical crosstalk; simplifying fabrication and enhancingresolution of multi-color sequentially illuminated LED displays;enabling fabrication of large modular arrays of a solid state lightemitting device; simplifying fabrication of next-generation vehicularheadlamps with multiple illumination zones and the ability toselectively illuminate or avoid illumination of selected illuminationtargets; and enabling projection of images or information on a targetillumination surface.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present disclosure. All suchimprovements and modifications are considered within the scope of theconcepts disclosed herein and the claims that follow.

What is claimed is:
 1. A multi-LED chip comprising: an array of LEDssupported by a substrate and arranged to transmit LED emissions througha plurality of light-transmissive portions of the substrate; at leastone lumiphoric material arranged on or over a light extraction surfaceof the substrate, wherein the at least one lumiphoric material isconfigured to receive at least a portion of the LED emissions andresponsively generate lumiphor emissions, and wherein the at least onelumiphoric material comprises a plurality of light output areassubstantially registered with the plurality of light-transmissiveportions; and a plurality of light segregation elements arranged atleast partially within the substrate, wherein light segregation elementsof the plurality of light segregation elements are arranged betweendifferent light-transmissive portions of the plurality oflight-transmissive portions, and the plurality of light segregationelements is configured to reduce passage of LED emissions between thedifferent light-transmissive portions; wherein the multi-LED chipcomprises at least one of the following features (i) or (ii): (i) thesubstrate comprises a light injection surface that opposes the lightextraction surface; a first group of light segregation elements of theplurality of light segregation elements extends from the light injectionsurface into an interior of the substrate; and a second group of lightsegregation elements of the plurality of light segregation elementsextends from the light extraction surface into the interior of thesubstrate; or (ii) the plurality of light segregation elements includesinternal portions extending from an interior of the substrate to thelight extraction surface, and includes external portions extendingbeyond the light extraction surface.
 2. The multi-LED chip of claim 1,wherein each LED of the array of LEDs is in a flip chip configuration.3. The multi-LED chip of claim 1, wherein each LED of the array of LEDscomprises an anode-cathode pair, and wherein the anode-cathode pair foreach LED of the array of LEDs is electrically isolated from theanode-cathode pair of each other LED of the array of LEDs.
 4. Themulti-LED chip of claim 3, wherein each LED of the array of LEDscomprises a front side and a back side that opposes the front side, thesubstrate of each LED is closer to the front side than to the back side,and the anode-cathode pair of each LED is arranged along the back side.5. The multi-LED chip of claim 1, wherein: the substrate comprises alight injection surface that opposes the light extraction surface; afirst group of light segregation elements of the plurality of lightsegregation elements extends from the light injection surface into aninterior of the substrate; and a second group of light segregationelements of the plurality of light segregation elements extends from thelight extraction surface into the interior of the substrate.
 6. Themulti-LED chip of claim 1, wherein the plurality of light segregationelements includes internal portions extending from an interior of thesubstrate to the light extraction surface, and includes externalportions extending beyond the light extraction surface.
 7. The multi-LEDchip of claim 6, further comprising a plurality of light extractionrecesses bounded by the light extraction surface and the externalportions of the plurality of light segregation elements, wherein the atleast one lumiphoric material is arranged at least partially within theplurality of light extraction recesses.
 8. The multi-LED chip of claim6, wherein the external portions are discontinuous relative to theinternal portions.
 9. The multi-LED chip of claim 1, wherein the lightextraction surface defines a plurality of light extraction recesses, andthe at least one lumiphoric material is arranged at least partiallywithin the plurality of light extraction recesses.
 10. The multi-LEDchip of claim 1, wherein the at least one lumiphoric material comprisesa first lumiphoric material corresponding to a first light output areaof the plurality of light output areas, and a second lumiphoric materialcorresponding to a second light output area of the plurality of lightoutput areas.
 11. The multi-LED chip of claim 1, wherein the pluralityof light segregation elements comprises a light-reflective material. 12.The multi-LED chip of claim 1, wherein the plurality of lightsegregation elements is registered with boundaries between at least someLEDs of the array of LEDs.
 13. The multi-LED chip of claim 1, whereinthe substrate comprises a growth substrate over which active layers ofthe array of LEDs were grown.
 14. A multi-LED chip comprising: an arrayof LEDs; at least one lumiphoric material, wherein the at least onelumiphoric material is configured to receive at least a portion of LEDemissions and responsively generate lumiphor emissions, wherein the atleast one lumiphoric material comprises a plurality of light outputareas; and a plurality of light segregation elements registered withboundaries between at least some LEDs of the array of LEDs; wherein theat least one lumiphoric material overlaps a portion of each lightsegregation element of the plurality of light segregation elements; andwherein a plurality of voids is defined in the at least one lumiphoricmaterial, and each void of the plurality of voids is registered with adifferent light segregation element of the plurality of lightsegregation elements.
 15. The multi-LED chip of claim 14, wherein eachLED of the array of LEDs is in a flip chip configuration.
 16. Themulti-LED chip of claim 14, wherein a plurality of light extractionrecesses are bounded by the plurality of light segregation elements anda light extraction surface of a light-transmissive substrate, andwherein the at least one lumiphoric material is arranged at leastpartially within the plurality of light extraction recesses.
 17. Themulti-LED chip of claim 14, wherein a light extraction surface of alight-transmissive substrate defines a plurality of light extractionrecesses, and the at least one lumiphoric material is arranged at leastpartially within the plurality of light extraction recesses.
 18. Themulti-LED chip of claim 14, further comprising a light transmissivesubstrate, wherein portions of the plurality of light segregationelements extend into an interior of the substrate.
 19. The multi-LEDchip of claim 18, wherein the at least one lumiphoric material comprisesa first lumiphoric material and a second lumiphoric material, the firstlumiphoric material is arranged to cover a first portion of a lightextraction surface of the light-transmissive substrate, and the secondlumiphoric material is arranged to cover a second portion of the lightextraction surface.
 20. The multi-LED chip of claim 14, wherein each LEDof the array of LEDs comprises an anode-cathode pair, and wherein theanode-cathode pair for each LED of the array of LEDs is electricallyisolated from the anode-cathode pair of each other LED of the array ofLEDs.
 21. The multi-LED chip of claim 20, wherein each LED of the arrayof LEDs comprises a front side and a back side that opposes the frontside, the substrate of each LED is closer to the front side than to theback side, and the anode-cathode pair of each LED is arranged along theback side.
 22. The multi-LED chip of claim 14, wherein the plurality oflight segregation elements comprises a light-reflective material.
 23. Amulti-LED chip comprising: a functional stack comprising a plurality ofsemiconductor layers and an active region; an array of LEDs formed inthe functional stack and defining a plurality of pixels, wherein eachLED of the array of LEDs comprises a light-transmissive substratematerial portion arranged over the active region; a plurality of lightsegregation elements registered with boundaries between at least somepixels of the plurality of pixels, the plurality of light segregationelements comprising reflective material arranged between substratematerial portions of different LEDs of the array of LEDs; and anunderfill material registered with boundaries between at least somepixels of the plurality of pixels; wherein the underfill materialextends continuously in a lateral direction between active regions ofeach LED of the array of LEDs; and wherein the plurality of lightsegregation elements comprises at least one recess configured to exposethe underfill material.
 24. The multi-LED chip of claim 23, wherein theunderfill material comprises a dielectric material.
 25. The multi-LEDchip of claim 23, wherein each substrate material portion isdiscontinuous from each other substrate material portion and isregistered with a different pixel of plurality of pixels.
 26. Themulti-LED chip of claim 25, wherein the at least one recess extendsthrough an entire thickness of substrate material portions of at leasttwo adjacent LEDs of the array of LEDs.